Image Forming Optical System and Electronic Image Pickup Apparatus Using Image Forming Optical System

ABSTRACT

An image forming optical system according to the present invention is characterized in that, in an image forming optical system having a positive lens group, a negative lens group, and an aperture stop, the positive lens group is disposed at an object side of the aperture stop,
         the positive lens group has a cemented lens which is formed by cementing a plurality of lenses,   in a rectangular coordinate system in which a horizontal axis is let to be Nd and a vertical axis is let to be νd, when a straight line indicated by Nd=α×νd+β (where, α=−0.017) is set,   Nd and νd of at least one lens forming the cemented lens is included in both of areas namely, an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1a), and a line when an upper limit value is in a range of the following conditional expression (1a), and of an area determined by following conditional expressions (2a) and (3a).       

       1.45&lt;β&lt;2.15  (1a) 
       1.30&lt;Nd&lt;2.20  (2a) 
       3&lt;νd&lt;12  (3a) 
     Here, Nd denotes a refractive index, and νd denotes an Abbe&#39;s number.

TECHNICAL FIELD

The present invention relates to an image forming optical system whichis used in an extremely small image pickup module, and an electronicimage pickup apparatus which includes the image forming optical system.

BACKGROUND ART

In recent years, a digital camera has been widely used as a nextgeneration camera replacing a silver salt 35 mm film camera. Recently,there has been increasing reduction in size, and thinning of a digitalcamera. Moreover, a camera function (hereinafter called as ‘image pickupmodule’) has been provided even in a portable telephone, the use ofwhich has also been increasing widely. For mounting this image pickupmodule in the portable telephone, an optical system has to be smallerand thinner than an optical system of the digital camera. Particularly,in a zoom lens, the reduction in size, and thinning has been sought.However, a zoom lens having a size reduced so as to mount in theportable telephone has not been known much.

As a typical means for reducing the size and thinning of the zoom lens,the following two means can be taken into consideration. In other words,

A. To use a collapsible lens barrel, and to accommodate the opticalsystem in a thickness (depth) of a casing. This collapsible lens barrelis a lens barrel having a structure in which the optical systemprotrudes from a camera casing, and is accommodated in the camera casingwhile carrying.

B. To accommodate the optical system in a direction of width or in adirection of height by adopting a dioptric system. This dioptric systemis an optical system having a structure in which an optical path(optical axis) of the optical system is folded by a reflecting opticalelement such as a mirror or a prism.

However, in the structure in which the abovementioned means A is used,the number of lenses forming the optical system or the number of movablelens group is more, and it is difficult to carry out the reduction insize, and the thinning.

Moreover, in the structure in which the abovementioned means B is used,it is easy to make the casing thin as compared to a case in which themeans in the abovementioned A is used, but an amount of movement of themovable lens group at the time of varying the power, and the number oflenses forming the optical system tend to increase. Therefore,volumetrically, it is not at all suitable for the reduction in size.

DISCLOSURE OF THE INVENTION

An image forming optical system according to the present invention ischaracterized in that, in an image forming optical system having apositive lens group, a negative lens group, and an aperture stop,

the positive lens group is disposed at an object side of the aperturestop,

the positive lens group has a cemented lens which is formed by cementinga plurality of lenses,

in a rectangular coordinate system in which a horizontal axis is let tobe Nd and a vertical axis is let to be νd, when a straight lineindicated by Nd=α×νd+β (where, α×=−0.017) is set,

Nd and νd of at least one lens forming the cemented lens are included inboth areas namely, an area which is determined by a line when a lowerlimit value is in a range of a following conditional expression (1a),and a line when an upper limit value is in a range of the followingconditional expression (1a), and of an area determined by followingconditionals expressions (2a) and (3a).

1.45<β<2.15  (1a)

1.30<Nd<2.20  (2a)

3<νd<12  (3a)

Here, Nd denotes a refractive index, and νd denotes an Abbe's number.

Moreover, an image forming optical system according to the presentinvention is characterized in that, in an image forming optical systemhaving a positive lens group, a negative lens group, and an aperturestop,

the positive lens group is disposed at an object side of the aperturestop,

the positive lens group has a cemented lens in which a plurality oflenses are cemented,

in a rectangular coordinate system in which, a horizontal axis is let tobe Nd and a vertical axis is let to be νd, when a straight lineindicated by Nd=α×νd+β (where, α=−0.017) is set,

Nd and νd of at least one lens forming the cemented lens are included inboth areas namely, an area which is determined by a line when a lowerlimit value is in a range of a following conditional expression (1b),and a line when an upper limit value is in a range of the followingconditional expression (1b), and of an area determined by followingconditional expressions (2b) and (3b).

1.45<β<2.15  (1b)

1.58<Nd<2.20  (2b)

3<νd<40  (3b)

Here, Nd denotes a refractive index, and νd denotes an Abbe's number.

Moreover, an electronic image pickup apparatus of the present inventionis characterized in that the electronic image pickup apparatus includesan image forming optical system mentioned in any one above, anelectronic image pickup element, and an image processing means which iscapable of processing image data obtained by image pickup by theelectronic image pickup element an image which is formed through theimage forming optical system, and outputting as image data in which ashape is changed upon processing, and in which the image forming opticalsystem is a zoom lens, and the zoom lens satisfies a followingconditional expression at a time of infinite object point focusing.

0.7<y ₀₇/(fw·tan ω_(07w))<0.96

where, y₀₇ is indicated as y₀₇=0.7 y₁₀ when, in an effective imagepickup surface (surface in which, image pickup is possible), a distancefrom a center up to a farthest point (maximum image height) is let to bey₁₀. Moreover, ω_(07w) is an angle with respect to an optical axis in adirection of an object point corresponding to an image point connectingfrom a center on the image pickup surface in a wide angle end up to aposition of y₀₇.

According to the present invention, it is possible to achieve a thinningand a size reduction of a volume of the image forming optical system,and further to have both of a widening of an angle and a favorablecorrection of various aberrations in the electronic image pickupapparatus of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view along an optical axis showing anoptical arrangement at the time of an infinite object point focusing ata wide angle end of a zoom lens according to a first embodiment of thepresent invention;

FIG. 2A, FIG. 2B, and FIG. 2C are diagrams showing a sphericalaberration, an astigmatism, a distortion, and a chromatic aberration ofmagnification at the time of the infinite object point focusing of thezoom lens according to the first embodiment of the present invention,where, FIG. 2A shows a state at the wide angle end, FIG. 2B shows anintermediate state, and FIG. 2C shows a state at a telephoto end;

FIG. 3 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a second embodiment ofthe present invention;

FIG. 4A, FIG. 4B, and FIG. 4C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the second embodiment of thepresent invention, where, FIG. 4A shows the state at the wide angle end,FIG. 4B shows the intermediate state, and FIG. 4C shows the state at thetelephoto end;

FIG. 5 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a third embodiment of thepresent invention;

FIG. 6A, FIG. 6B, and FIG. 6C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the third embodiment of thepresent invention, where, FIG. 6A shows the state at the wide angle end,FIG. 6B shows the intermediate state, and FIG. 6C shows the state at thetelephoto end;

FIG. 7 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a fourth embodiment ofthe present invention;

FIG. 8A, FIG. 8B, and FIG. 8C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the fourth embodiment of thepresent invention, where, FIG. 8A shows the state at the wide angle end,FIG. 8B shows the intermediate state, and FIG. 8C shows the state at thetelephoto end;

FIG. 9 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a fifth embodiment of thepresent invention;

FIG. 10A, FIG. 10B, and FIG. 10C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the fifth embodiment of thepresent invention, where, FIG. 10A shows the state at the wide angleend, FIG. 10B shows the intermediate state, and FIG. 10C shows the stateat the telephoto end;

FIG. 11 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a sixth embodiment of thepresent invention;

FIG. 12A, FIG. 12B, and FIG. 12C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the sixth embodiment of thepresent invention, where, FIG. 12A shows the state at the wide angleend, FIG. 12B shows the intermediate state, and FIG. 12C shows the stateat the telephoto end;

FIG. 13 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a seventh embodiment ofthe present invention;

FIG. 14A, FIG. 14B, and FIG. 14C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the seventh embodiment of thepresent invention, where, FIG. 14A shows the state at the wide angleend, FIG. 14B shows the intermediate state, and FIG. 14C shows the stateat the telephoto end;

FIG. 15 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to an eighth embodiment ofthe present invention;

FIG. 16A, FIG. 16B, and FIG. 16C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the eighth embodiment of thepresent invention, where, FIG. 16A shows the state at the wide angleend, FIG. 16B shows the intermediate state, and FIG. 16C shows the stateat the telephoto end;

FIG. 17 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a ninth embodiment of thepresent invention;

FIG. 18A, FIG. 18B, and FIG. 18C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the ninth embodiment of thepresent invention, where, FIG. 18A shows the state at the wide angleend, FIG. 18B shows the intermediate state, and FIG. 18C shows the stateat the telephoto end;

FIG. 19 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a tenth embodiment of thepresent invention;

FIG. 20A, FIG. 20B, and FIG. 20C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the tenth embodiment of thepresent invention, where, FIG. 20A shows the state at the wide angleend, FIG. 20B shows the intermediate state, and FIG. 20C shows the stateat the telephoto end;

FIG. 21 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to an eleventh embodiment ofthe present invention;

FIG. 22A, FIG. 22B, and FIG. 22C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the eleventh embodiment of thepresent invention, where, FIG. 22A shows the state at the wide angleend, FIG. 22B shows the intermediate state, and FIG. 22C shows the stateat the telephoto end;

FIG. 23 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a twelfth embodiment ofthe present invention;

FIG. 24A, FIG. 24B, and FIG. 24C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the twelfth embodiment of thepresent invention, where, FIG. 24A shows the state at the wide angleend, FIG. 24B shows the intermediate state, and FIG. 24C shows the stateat the telephoto end;

FIG. 25 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a thirteenth embodimentof the present invention;

FIG. 26A, FIG. 26B, FIG. 26C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the thirteenth embodiment of thepresent invention, where, FIG. 26A shows the state at the wide angleend, FIG. 26B shows the intermediate state, and FIG. 26C shows the stateat the telephoto end;

FIG. 27 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a fourteenth embodimentof the present invention;

FIG. 28A, FIG. 28B, and FIG. 28C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the fourteenth embodiment of thepresent invention, where, FIG. 28A shows the state at the wide angleend, FIG. 28B shows the intermediate state, and FIG. 28C shows the stateat the telephoto end;

FIG. 29 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a fifteenth embodiment ofthe present invention;

FIG. 30A, FIG. 30B, and FIG. 30C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the fifteenth embodiment of thepresent invention, where, FIG. 30A shows the state at the wide angleend, FIG. 30B shows the intermediate state, and FIG. 30C shows the stateat the telephoto end;

FIG. 31 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a sixteenth embodiment ofthe present invention;

FIG. 32A, FIG. 32B, and FIG. 32C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the sixteenth embodiment of thepresent invention, where, FIG. 32A shows the state at the wide angleend, FIG. 32B shows the intermediate state, and FIG. 32C shows the stateat the telephoto end;

FIG. 33 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a seventeenth embodimentof the present invention;

FIG. 34A, FIG. 34B, and FIG. 34C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the seventeenth embodiment of thepresent invention, where, FIG. 34A shows the state at the wide angleend, FIG. 34B shows the intermediate state, and FIG. 34C shows the stateat the telephoto end;

FIG. 35 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to an eighteenth embodimentof the present invention;

FIG. 36A, FIG. 36B, and FIG. 36C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the eighteenth embodiment of thepresent invention, where, FIG. 36A shows the state at the wide angleend, FIG. 36B shows the intermediate state, and FIG. 36C shows the stateat the telephoto end;

FIG. 37 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a nineteenth embodimentof the present invention;

FIG. 38A, FIG. 38B, and FIG. 38C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the nineteenth embodiment of thepresent invention, where, FIG. 38A shows the state at the wide angleend, FIG. 38B shows the intermediate state, and FIG. 38C shows the stateat the telephoto end;

FIG. 39 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a twentieth embodiment ofthe present invention;

FIG. 40A, FIG. 40B, and FIG. 40C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the twentieth embodiment of thepresent invention, where, FIG. 40A shows the state at the wide angleend, FIG. 40B shows the intermediate state, and FIG. 40C shows the stateat the telephoto end;

FIG. 41 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a twenty first embodimentof the present invention;

FIG. 42A, FIG. 42B, and FIG. 42C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the twenty first embodiment ofthe present invention, where, FIG. 42A shows the state at the wide angleend, FIG. 42B shows the intermediate state, and FIG. 42C shows the stateat the telephoto end;

FIG. 43 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a twenty secondembodiment of the present invention;

FIG. 44A, FIG. 44B, and FIG. 44C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the twenty second embodiment ofthe present invention, where, FIG. 44A shows the state at the wide angleand, FIG. 44B shows the intermediate state, and FIG. 44C shows the stateat the telephoto end;

FIG. 45 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a twenty third embodimentof the present invention;

FIG. 46A, FIG. 46B, and FIG. 46C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the twenty third embodiment ofthe present invention, where, FIG. 46A shows the state at the wide angleend, FIG. 46B shows the intermediate state, and FIG. 46C shows the stateat the telephoto end;

FIG. 47 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a twenty fourthembodiment of the present invention;

FIG. 48A, FIG. 48B, and FIG. 48C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the twenty fourth embodiment ofthe present invention, where, FIG. 48A shows the state at the wide angleend, FIG. 48B shows the intermediate state, and FIG. 48C shows the stateat the telephoto end;

FIG. 49 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a twenty fifth embodimentof the present invention;

FIG. 50A, FIG. 50B, and FIG. 50C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the twenty fifth embodiment ofthe present invention, where, FIG. 50A shows the state at the wide angleend, FIG. 50B shows the intermediate state, and FIG. 50C shows the stateat the telephoto end;

FIG. 51 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a twenty sixth embodimentof the present invention;

FIG. 52A, FIG. 52B, and FIG. 52C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the twenty sixth embodiment ofthe present invention, where, FIG. 52A shows the state at the wide angleend, FIG. 52B shows the intermediate state, and FIG. 52C shows the stateat the telephoto end;

FIG. 53 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a twenty seventhembodiment of the present invention;

FIG. 54A, FIG. 54B, and FIG. 54C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the twenty seventh embodiment ofthe present invention, where, FIG. 54A shows the state at the wide angleend, FIG. 54B shows the intermediate state, and FIG. 54C shows the stateat the telephoto end;

FIG. 55 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a twenty eighthembodiment of the present invention;

FIG. 56A, FIG. 56B, and FIG. 56C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the twenty eighth embodiment ofthe present invention, where, FIG. 56A shows the state at the wide angleend, FIG. 56B shows the intermediate state, and FIG. 56C shows the stateat the telephoto end;

FIG. 57 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a twenty ninth embodimentof the present invention;

FIG. 58A, FIG. 58B, and FIG. 58C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the twenty ninth embodiment ofthe present invention, where, FIG. 58A shows the state at the wide angleend, FIG. 58B shows the intermediate state, and FIG. 58C shows the stateat the telephoto end;

FIG. 59 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a thirtieth embodiment ofthe present invention;

FIG. 60A, FIG. 60B, and FIG. 60C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the thirtieth embodiment of thepresent invention, where, FIG. 60A shows the state at the wide angleend, FIG. 60B shows the intermediate state, and FIG. 60C shows the stateat the telephoto end;

FIG. 61 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a thirty first embodimentof the present invention;

FIG. 62A, FIG. 62B, and FIG. 62C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the thirty first embodiment ofthe present invention, where, FIG. 62A shows the state at the wide angleend, FIG. 62B shows the intermediate state, and FIG. 62C shows the stateat the telephoto end;

FIG. 63 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a thirty secondembodiment of the present invention;

FIG. 64A, FIG. 64B, and FIG. 64C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the thirty second embodiment ofthe present invention, where, FIG. 64A shows the state at the wide angleend, FIG. 64B shows the intermediate state, and FIG. 64C shows the stateat the telephoto end;

FIG. 65 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a thirty third embodimentof the present invention;

FIG. 66A, FIG. 66B, and FIG. 66C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the thirty third embodiment ofthe present invention, where, FIG. 66A shows the state at the wide angleend, FIG. 66B shows the intermediate state, and FIG. 66C shows the stateat the telephoto end;

FIG. 67 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a thirty fourthembodiment of the present invention;

FIG. 68A, FIG. 68B, and FIG. 68C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the thirty fourth embodiment ofthe present invention, where, FIG. 68A shows the state at the wide angleend, FIG. 68B shows the intermediate state, and FIG. 68C shows the stateat the telephoto end;

FIG. 69 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a thirty fifth embodimentof the present invention;

FIG. 70A, FIG. 70B, FIG. 70C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the thirty fifth embodiment ofthe present invention, where, FIG. 70A shows the state at the wide angleend, FIG. 70B shows the intermediate state, and FIG. 70C shows the stateat the telephoto end;

FIG. 71 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a thirty sixth embodimentof the present invention;

FIG. 72A, FIG. 72B, and FIG. 72C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the thirty sixth embodiment ofthe present invention, where, FIG. 72A shows the state at the wide angleend, FIG. 72B shows the intermediate state, and FIG. 72C shows the stateat the telephoto end;

FIG. 73 is a cross-sectional view along the optical axis showing anoptical arrangement at the wide angle end of a zoom lens according to athirty seventh embodiment of the present invention;

FIG. 74A, FIG. 74B, and FIG. 74C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the thirty seventh embodiment ofthe present invention, where, FIG. 74A shows the state at the wide angleend, FIG. 74B shows the intermediate state, and FIG. 74C shows the stateat the telephoto end;

FIG. 75 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a thirty eighthembodiment of the present invention;

FIG. 76A, FIG. 76B, and FIG. 76C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the thirty eighth embodiment ofthe present invention, where, FIG. 76A shows the state at the wide angleend, FIG. 76B shows the intermediate state, and FIG. 76C shows the stateat the telephoto end;

FIG. 77 is a frontward perspective view showing an appearance of adigital camera 40 in which a zoom optical system according to thepresent invention is incorporated;

FIG. 78 is a rearward perspective view of the digital camera 40;

FIG. 79 is a cross-sectional view showing an optical arrangement of thedigital camera 40;

FIG. 80 is a frontward perspective view of a personal computer 300 withits cover opened, which is an example of an information processingapparatus with the built-in zoom optical system of the presentinvention, as an objective optical system;

FIG. 81 is a cross-sectional view of a photographic optical system 303of the personal computer 300;

FIG. 82 is a side view of the personal computer 300; and

FIG. 83A, FIG. 83B, and FIG. 83C are diagrams showing a portabletelephone which is an example of the information processing apparatus inwhich the zoom optical system of the present invention is built in asthe photographing optical system, where, FIG. 83A is a front view of aportable telephone 400, FIG. 83B is a side view of the portabletelephone 400, and FIG. 83C is a cross-sectional view of a photographicoptical system 405.

BEST MODE FOR CARRYING OUT THE INVENTION

Prior to a description of embodiments, an action and an effect of thepresent invention will be described below.

An image forming optical system of the present invention, where theimage forming optical system includes a positive lens group, a negativelens group, and an aperture stop, has a basic structure in which thepositive lens group is disposed at an object side of the aperture stop,and the positive lens group includes a cemented lens which is formed bycementing a plurality of lenses.

In this manner, in the basic structure, since the cemented lens is usedin the positive lens group disposed at on the object side of theaperture stop, a fluctuation in a chromatic aberration of magnificationparticularly in a zoom lens, at the time of varying a power is easilysuppressed. Moreover, with a fewer number of lenses, it is possible tosuppress sufficiently an occurrence of a color blur over an entirezooming area. Moreover, since it is possible to make thin the positivelens group (positive lens group disposed at the object side of theaperture stop) which tends to be thick, it is possible to make shallow(short) a distance from a vertex of a lens surface at a farthest side ofthe object, up to an entrance pupil. As a result of this, it is possibleto make thin a lens group other than the lens group disposed at theobject side of the aperture stop.

Moreover, in the abovementioned basic structure, it is preferable thatat least one lens forming the cemented lens has the followingcharacteristics. In other words, in a rectangular coordinate system inwhich a horizontal axis is let to be Nd and a vertical axis is let to beνd, when a straight line indicated by Nd=α×νd+β (where, α=−0.017) isset, it is desirable that Nd and νd of at least one lens forming thecemented lens are included in both areas namely, an area which isdetermined by a line when a lower limit value is in a range of afollowing conditional expression (1a), and a line when an upper limitvalue is in a range of the following conditional expression (1a), and anarea determined by following conditional expressions (2a) and (3a).

1.45<β<2.15  (1a)

1.30<Nd<2.20  (2a)

3<νd<12  (3a)

Here, Nd denotes a refractive index, and νd denotes an Abbe's number.

Here, a glass means a lens material such as a glass and a resin.Moreover, as a cemented lens, a lens in which a plurality of lenses madeof a glass selected appropriately is cemented, is selected.

When value is lower than the lower limit value in the conditionalexpression (1a), since a refractive index is low, an effect when anaspheric surface is provided on a side which is in contact with air issmall, and a correction of a spherical aberration, a coma aberration,and a distortion becomes difficult. Or, since the Abbe's number is low,a correction of a chromatic aberration, as an extremely thin cementedlens is possible, but when the side in contact with air is made to be anaspheric surface, a chromatic coma and a chromatic aberration ofmagnification of high order is susceptible to occur, and a degree offreedom of an aberration correction is decreased.

When a value is higher than the upper limit value in the conditionalexpression (1a), since a power and a thickness of the cemented lens isrequired to be more than a certain magnitude for the correction of thechromatic aberration, it become susceptible to be effected by opticalcharacteristics which depend on an environment of the material.

When a value is lower than the lower limit value in the conditionalexpression (2a), the effect when the aspheric surface is provided on theside which is in contact with air is small, and the correction of thespherical aberration, the comatic aberration, and the distortion becomesdifficult.

When a value is higher than the upper limit value in the conditionalexpression (2a), in a case of a material which includes organicproperties, when the refractive index is excessively high, a temperaturevariance becomes excessively high, and optical characteristics whichdepend on the environment are susceptible to become unstable. Moreover,a reflectivity becomes excessively high, and a ghost is susceptible tooccur even when coating is optimized.

When a value is lower than the lower limit value in the conditionalexpression (3a), the correction of the chromatic aberration, as anextremely thin cemented lens is possible, but when the side in contactwith air is made to be an aspheric surface, the chromatic coma and thechromatic aberration of magnification of high order are susceptible tooccur, and the degree of freedom of the aberration correction isdecreased.

When a value is higher than the upper limit value in the conditionalexpression (3a), it is necessary to enhance a refracting power of thecemented lens for correcting the chromatic aberration, and it isadvantageous for a correction of a Petzval's sum, but it becomessusceptible to be effected by the optical characteristics which dependon the environment of the material.

It is more preferable when a following conditional expression (1a′) issatisfied.

1.48<β<2.04  (1a′)

Furthermore, it is even more preferable when a following conditionalexpression (1a″) is satisfied.

1.50<β<2.00  (1a″)

Moreover, it is more preferable when a following conditional expression(2a′) is satisfied.

1.58<Nd<2.10  (2a′)

Furthermore, it is even more preferable when a following conditionalexpression (2a″) is satisfied.

1.63<Nd<1.95  (2a″)

Moreover, it is more preferable when a following conditional expression(3a′) is satisfied.

5<νd<10  (3a′)

Furthermore, it is more preferable when a following conditionalexpression (3a″) is satisfied.

6<νd<9  (3a″)

Or, in the abovementioned basic structure, it is preferable that atleast one lens forming the cemented lens has the followingcharacteristics. In other words, in a rectangular coordinate system inwhich a horizontal axis is let to be Nd and a vertical axis is let to beνd, when a straight line indicated by Nd=α×νd+β (where, α=−0.017) isset, it is desirable that Nd and νd of at least one lens forming thecemented lens is included in both areas namely, an area which isdetermined by a line when a lower limit value is in a range of afollowing conditional expression (1b), and a line when an upper limitvalue is in a range of the following conditional expression (1b), and ofan area determined by following conditional expressions (2b) and (3b).

1.45<β<2.15  (1b)

1.58<Nd<2.20  (2b)

3<νd<40  (3b)

Here, Nd denotes the refractive index, and νd denotes the Abbe's number.

When a value is lower than the lower limit value in the conditionalexpression (1b), since the refractive index is low, the effect when theaspheric surface is provided on the side which is in contact with air issmall, and the correction of the spherical aberration, the comaaberration, and the distortion becomes difficult. Or, since the Abbe'snumber is low, the correction of the chromatic aberration, as anextremely thin cemented lens is possible, but when the side in contactwith air is made to be an aspheric surface, the chromatic coma and thechromatic aberration of magnification of high order are susceptible tooccur, and the degree of freedom of the aberration correction isdecreased.

When a value is higher than the upper limit value in the conditionalexpression (1b), a correction level of the chromatic aberration and thePetzval's sum become same as of a general optical glass lens, andcharacteristics of the present invention are not achieved.

When a value is lower than the lower limit value in the conditionalexpression (2b), the effect when the aspheric surface is provided on theside which is in contact with air is small, and the correction of thespherical aberration, the coma aberration, and the distortion becomesdifficult.

When a value is higher than the upper limit value in the conditionalexpression (2b), in the case of a material which includes organicproperties, when the refractive index is excessively high, thetemperature variance becomes excessively high, and the opticalcharacteristics which depend on the environment are susceptible tobecome unstable. Moreover, the reflectivity becomes excessively high,and a ghost is susceptible to occur even when the coating is optimized.

When a value is lower than the lower limit value in the conditionalexpression (3b), the correction of the chromatic aberration, as anextremely thin cemented lens is possible, but when the side in contactwith air is made to be an aspheric surface, the chromatic coma and thechromatic aberration of magnification of high order are susceptible tooccur, and the degree of freedom of the aberration correction isdecreased.

When a value is higher than the upper limit value in the conditionalexpression (3b), it is necessary to enhance the refracting power of thecemented lens for correcting the chromatic aberration, and it isadvantageous for the correction of the Petzval's sum, but it becomessusceptible to be effected by the optical characteristics which dependon the environment of the material.

It is more preferable when a following conditional expression (1b′) issatisfied.

1.48<β<2.04  (1b′)

Furthermore, it is even more preferable when a following conditionalexpression (1b″) is satisfied.

1.50<β<2.00  (1b″)

Moreover, it is more preferable when a following conditional expression(2b′) is satisfied.

1.60<Nd<2.10  (2b′)

Furthermore, it is more preferable when a following conditionalexpression (2b″) is satisfied.

1.63<Nd<1.95  (2b″)

Moreover, it is more preferable when a following conditional expression(3b′) is satisfied.

5<νd<30  (3b′)

Furthermore, it is more preferable when a following conditionalexpression (3b″) is satisfied.

6<νd<25  (3b″)

Moreover, it is preferable that the cemented lens is formed by a lenshaving the values of Nd and νd which are included in both the areasmentioned above (hereinafter, called as a ‘predetermined lens’), and alens other than the predetermined lens, and a center thickness along anoptical axis of the predetermined lens is less than a center thicknessalong an optical axis of the other lens. By making such an arrangement,it is possible to realize a more favorable correction of each aberrationmentioned above, and thinning of the lens group.

Furthermore, the cemented lens may be a compound lens which is formed byclosely adhering and hardening a resin on a lens surface (lens surfaceof the other lens), in order to improve a manufacturing accuracy. Here,the resin which is adhered and hardened corresponds to the predeterminedlens.

Moreover, the cemented lens may be a compound lens which is formed byclosely adhering and hardening a glass on the lens surface (lens surfaceof the other lens), as it is advantageous for resistance such as a lightresistance and a chemical resistance. Here, the glass which is adheredand hardened corresponds to the predetermined lens.

P16 Line 6

Furthermore, in the cemented lens, a center thickness t1 along theoptical axis of the predetermined lens (one lens in which Nd and νd areincluded in both the areas mentioned above) may satisfy a followingconditional expression (4), in order to make a size small and to carryout molding stably.

0.22<t1<2.0  (4)

It is more preferable that a following conditional expression (4′) issatisfied.

0.3<t1<1.5  (41)

Furthermore, it is even more preferable that a following conditionalexpression (4″) is satisfied.

0.32<t1<1.0  (4″)

Moreover, the image forming optical system may be a zoom lens in whichthe closest side of an object is a positive group, from a viewpoint ofhaving a high magnification of the zoom, and improving a brightness ofthe lens.

Furthermore, the image forming optical system may be a zoom lens inwhich the closest side of an object is a negative group, for making thesize small.

Moreover, the image forming optical system may have a prism for folding,and for facilitating thinning of an optical system with respect to adirection of photography.

Furthermore, in the image forming optical system, the prism may be in agroup on the closest side of an object, for facilitating the thinning.

Incidentally, when a pixel size of the electronic image pickup elementbecomes smaller than a certain size, a component of a frequency higherthan a Nyquist frequency is eliminated due to an effect of diffraction.Therefore, when this is used, it is possible to omit an optical low-passfilter. This is preferable from a point of making the entire opticalsystem extremely thin.

For this, it is preferable that a following conditional expression (6)is satisfied.

Fw≧a (μm)  (6)

where, Fw is a full-aperture F value at wide angle end, and “a” is adistance between pixels in a horizontal direction of the electronicimage pickup element (unit: μm).

When the conditional expression (6) is satisfied, the optical low-passfilter is not required to be disposed in an optical path. Accordingly itis possible to make the optical system small.

In a case of satisfying the conditional expression (6), it is preferablethat the aperture stop is let to be open only. This means that theoptical system in this case is an optical system with a constantdiameter of the aperture stop all the time. Moreover, in the opticalsystem in this case, since an operation of narrowing is not necessary,it is possible to omit a narrowing mechanism. Accordingly, the size canbe made small saving that much space. When the conditional expression(6) is not satisfied, the optical low-pass filter is necessary.

Moreover, it is more preferable that a conditional expression (6′) issatisfied.

Fw≧1.2a (μm)  (6′)

Furthermore, it is even more preferable that a conditional expression(6″) is satisfied.

Fw≧1.4a (μm)  (6″)

Finally, an electronic image pickup apparatus will be described below.As the electronic image pickup apparatus, an electronic image pickupapparatus in which both a thinning of depth and a widening of imageangle are realized is preferable.

Here, an infinite object is let to be imaged by an optical system whichhas no distortion. In this case, since the image which is formed has nodistortion,

f=y/tan ω

holds.

Here, y is a height of an image point from an optical axis, f is a focallength of the image forming system, and ω is an angle with respect to anoptical axis in a direction of an object point corresponding to theimage point connecting from a center on an image pickup surface up to aposition of y.

On the other hand, when the optical system has a barrel distortion,

f>y/tan ω

holds. In other words, when f and y are let to be constant values, ωbecomes a substantial value.

Therefore, in the electronic image pickup apparatus, it is preferable touse a zoom lens as the image forming optical system. As a zoom lens,particularly in a focal length near a wide-angle end, an optical systemhaving a substantial barrel distortion may be used intentionally. Inthis case, since a purpose is served without correcting the distortion,it is possible to achieve the widening of the image angle of the opticalsystem. However, an image of the object is formed on the electronicimage pickup element, in a state of having the barrel distortion.Therefore, in the electronic image pickup apparatus, image data obtainedby the electronic image pickup element is processed by an imageprocessing. In this process, the image data (a shape of the image) ischanged such that the barrel distortion is corrected. By changing theimage data, image data takes a shape almost similar to the object.Accordingly, based on this image data, the image of the object may beoutput to a CRT or a printer.

Here, as the image pickup optical system, an image pickup optical systemwhich satisfies a following conditional expression (7) at the time ofinfinite object point focusing, may be adopted.

0.7<y ₀₇/(fw·tan ω_(07w))<0.96  (7)

where, y₀₇ is indicated as y₀₇=0.7y₁₀ when, in an effective image pickupsurface (surface in which image pickup is possible), a distance from acenter up to a farthest point (maximum image height) is let to be y₁₀.Moreover, ω_(07w) is an angle with respect to an optical axis in adirection of an object point corresponding to an image point connectingfrom a center on the image pickup surface in a wide angle end up to aposition of y₀₇.

The conditional expression (7) mentioned above is an expression in whichan amount of the barrel distortion in a zoom wide-angle end isregulated. When the conditional expression (7) is satisfied, it ispossible to fetch information of the wide image angle without making theoptical system enlarged. An image which is distorted to barrel shape issubjected to photoelectric conversion, and becomes image data which isdistorted to barrel shape. However, on the image data which is distortedto the barrel shape, a process equivalent to a shape change of the imageis carried out electrically by the image processing means which is asignal processing system of the electronic image pickup apparatus. Whenthis process is carried out, even when the image data output from theimage processing means is reproduced finally by a display apparatus(unit), the distortion is corrected, and an image almost similar to ashape of an object to be photographed is obtained.

Here, when a value is higher than the upper limit value in theconditional expression (7), particularly when a value close to 1 is tobe taken, it is possible to carry out by the image processing means acorrection equivalent to a correction in which the distortion iscorrected favorably optically, but it is difficult to fetch an imageover a wide angle of visibility. On the other hand, a value is lowerthan the lower limit value in the conditional expression (7), rate ofenlarging in a direction of radiating in a portion around an image anglewhen the image distortion due to the distortion of the optical system iscorrected by the image processing means, becomes excessively high. As aresult of this, a decline in a sharpness of the area around the imagebecomes remarkable.

On the other hand, by satisfying the conditional expression (7), it ispossible to widen the angle (make an image angle in a vertical directionin the distortion to be 38° or more) and to make small the opticalsystem.

Moreover, it is more preferable when a following conditional expression(7′) is satisfied.

0.75<y ₀₇/(fw·tan ω_(07w))<0.94  (7′)

Furthermore, it is even more preferable when a following conditionalexpression (7″) is satisfied.

0.80<y ₀₇/(fw·tan ω_(07w))<0.92  (7″)

The image forming optical system of the present invention, even when anelectronic image pickup element of a large number of pixels is used, iscapable of achieving thinning and reduction in size of a volume of theimage forming optical system, by satisfying or providing each ofconditional expressional and structural characteristics mentioned above,and realizing a favorable correction of aberration. Moreover, the imageforming optical system of the present invention is capable of providing(satisfying) in combination the conditional expressional and structuralcharacteristics mentioned above. In this case, it is possible to achievefurther reduction in size and thinning, or the favorable aberrationcorrection. Moreover, in the electronic image pick up apparatus havingthe image forming optical system of the present invention, it ispossible to achieve the thinning and reduction is size of the volume ofthe image forming optical system, and further, to have both of thefavorable correction of various aberrations, and widening of the angle.

Embodiments of the present invention will be described below by usingdiagrams.

As a zoom lens of the present invention, a five-groups structure or afour-groups structure can be taken into consideration. In a zoom lens ofthe five-group structure, it is preferable to dispose each lens group inan order of a first lens group having a positive refracting power, asecond lens group having a negative refracting power, a third lens grouphaving a positive refracting power, a fourth lens group having anegative refracting power, and a fifth lens group having a positiverefracting power, from an object side.

Here, it is preferable that the first lens group includes a negativelens, a prism, and a cemented lens. At this time, it is preferable todispose these in an order of the negative lens, the prism, and thecemented lens, from the object side. Moreover, it is preferable to formthe cemented lens by a positive lens and a negative lens, and to disposethe cemented lens such that the negative lens is positioned toward theobject side. The first lens group may be formed by one negative lens,one prism, and one cemented lens. In this case, the cemented lens isformed by one positive lens and one negative lens.

Moreover, it is preferable that the second lens group includes apositive lens and a negative lens. At this time, it is preferable todispose these in an order of the negative lens and the positive lensfrom the object side. The second lens group may include only onepositive lens and one negative lens.

Furthermore, it is preferable that the third lens group includes apositive lens and a negative lens. At this time, it is preferable toform a cemented lens by the positive lens and the negative lens, and todispose the cemented lens such that the positive lens is positioned atthe object side. The third lens group may be formed by only one cementedlens. In this case, the cemented lens is formed by one positive lens andone negative lens.

Moreover, it is preferable that the fourth lens group includes anegative lens. At this time, it is preferable to form the fourth lensgroup by only one negative lens.

Furthermore, it is preferable that the fifth lens group includes apositive lens. At this time, it is preferable to form the fifth lensgroup by only one positive lens.

Moreover, in a zoom lens of the four-groups structure, it is preferableto dispose each lens group in an order of a first lens group having anegative refracting power, a second lens group having a positiverefracting power, a third lens group having a negative refracting power,and a fourth lens group having a positive refracting power, from theobject side.

Here, it is preferable that the first lens group includes a negativelens, a prism, and a cemented lens. At this time, it is preferable todispose these in an order of the negative lens, the prism, and thecemented lens from the object side. Moreover, it is preferable to formthe cemented lens by a positive lens and a negative lens, and to disposethe cemented lens such that the positive lens is positioned at theobject side. The first lens group may be formed by only one negativelens, one prism, and one cemented lens. In this case, the cemented lensis formed by one positive lens and one negative lens.

Moreover, it is preferable that the second lens group includes apositive lens and a negative lens. At this time, it is preferable toform a cemented lens by the positive lens and the negative lens, and todispose the cemented lens such that the positive lens is positioned atthe object side. The second lens group may be formed by only onecemented lens. In this case, the cemented lens is formed by one positivelens and one negative lens.

Furthermore, it is preferable that the third lens group includes apositive lens and a negative lens. At this time, it is preferable toform a cemented lens by the positive lens and the negative lens, and todispose the cemented lens such that the negative lens is positioned atthe object side. The third lens group may include only one cementedlens. In this case, the cemented lens is formed by one positive lens andone negative lens.

Moreover, it is preferable that the fourth lens group includes apositive lens and a negative lens. At this time, it is preferable toform a cemented lens by the positive lens and the negative lens, and todispose the cemented lens such that the positive lens is positioned atthe object side. The fourth lens group may be formed by only onecemented lens. In this case, the cemented lens includes one positivelens and one negative lens.

It is possible to distribute a refracting power of one lens into twolenses. Accordingly, in each of the lens groups mentioned above, it ispossible to substitute one lens by two lenses. However, from a point ofview of the reduction in size and thinning, it is desirable to let thenumber of lenses to be substituted by two lenses in each group to beone.

FIRST EMBODIMENT

FIG. 1 is a cross-sectional view along an optical axis showing anoptical arrangement at the time of an infinite object point focusing ata wide angle end of a zoom lens according to a first embodiment.

FIG. 2A, FIG. 2B, and FIG. 2C are diagrams showing a sphericalaberration, an astigmatism, a distortion, and a chromatic aberration ofmagnification at the time of the infinite object point focusing of thezoom lens according to the first embodiment of the present invention,where, FIG. 2A shows a state at the wide angle end, FIG. 2B shows anintermediate state, and FIG. 2C shows a state at a telephoto end.

The zoom lens of the first embodiment, as shown in FIG. 1, has a firstlens group G1, a second lens group G2, an aperture stop S, a third lensgroup G3, a fourth lens group G4, and a fifth lens group G5, in thisorder from the object side. In the diagram, LPF is a low-pass filter, CGis a cover glass, and I is an image pickup surface of a electronic imagepickup element.

The first lens group G1 includes a negative meniscus lens L111 having aconvex surface directed toward the object side, a prism L112, and acemented lens which is formed by a negative meniscus lens L113 having aconvex surface directed toward the object side, and a biconvex lensL114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121, and a positivemeniscus lens L122 having a convex surface directed toward the objectside, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconvex lens L131 and a biconcave lens L132, and has a positiverefracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having aconvex surface directed toward the object side, and has a negativerefracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has apositive refracting power as a whole.

At the time of zooming from the wide-angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward animage side, the aperture stop S is fixed, the third lens group G3 movestoward the object side, the fourth lens group G4 moves once toward theimage side, and then moves toward the object side, and the fifth lensgroup G5 moves toward the image side.

Aspheric surfaces are provided on a surface toward the object side, ofthe negative meniscus lens L113 having the convex surface directedtoward the object in the first lens group G1, both surfaces of thebiconcave lens L121 in the second lens group G2, a surface toward theobject side, of the biconvex lens L131, and a surface toward the imageside of the biconcave lens L132 in the third lens group G3, and asurface toward the object side, of the biconvex lens L142 in the fifthlens group G5.

Next, numerical data of optical members forming the zoom lens of thefirst embodiment will be enumerated.

In the numerical data of the first embodiment, r1, r2, . . . denote aradius of curvature of each lens surface, d1, d2, . . . denote athickness or an air space of each lens, nd1, nd2, . . . denote arefractive index at d line of each lens, νd1, νd2, . . . denote theAbbe's number for each lens, Fno. denotes an F number, f denotes a focallength of an overall system, and D0 denotes a distance from the objectto a first surface.

An aspheric surface shape is expressed by a following expression when adirection of an optical axis is let to be z, a direction orthogonal tothe optical axis is let to be y, a conical coefficient is let to be K,and an aspheric coefficient is let to be A4, A6, A8, and A10.

z=(y ² /r)/[1{1−(1+K)(y/r)²}^(1/2) ]+A4y ⁴ +A6y ⁶ +A8y ⁸ +A10y ¹⁰

Moreover, E denotes a power of 10. These symbols of data values arecommon even in numerical data of embodiments which will be describedlater. The conical coefficient may also be denoted by k.

Next, numerical data of the first embodiment will be enumerated.

Numerical data 1 r1 = 129.769 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 9.996d2 = 2.9 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 =20.456 d5 = 0.1 Nd5 = 1.41244 νd5 = 12.42 (Aspheric surface) r6 = 17.047d6 = 3.54 Nd6 = 1.741 νd6 = 52.64 r7 = −40.493 d7 = D7 r8 = −78.921 d8 =0.8 Nd8 = 1.8061 νd8 = 40.92 (Aspheric surface) r9 = 5.100 d9 = 0.7(Aspheric surface) r10 = 6.857 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11= 101.37 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 8.626 d13 = 6.74Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −9.767 d14 = 1 Nd14= 1.84666 νd14 = 23.78 r15 = 48.970 d15 = D15 (Aspheric surface) r16 =23.269 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 9.679 d17 = D17 r18 =10.881 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 =−248.017 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd2 = 264.14 r23 = ∞ d23 =D23 Aspherical coefficients  5th surface k = 0 A4 = 7.03408E−06 A6 =1.07494E−07 A8 = 0  8th surface k = 0 A4 = 5.78353E−04 A6 = −2.76230E−05A8 = 4.54522E−07  9th surface k = 0 A4 = 1.19342E−04 A6 = −3.10809E−05A8 = −1.06052E−06 13th surface k = 0 A4 = 6.44238E−05 A6 = 1.52064E−06A8 = −2.73314E−08 15th surface k = 0 A4 = 4.61191E−04 A6 = 1.41022E−05A8 = −1.40537E−07 18th surface k = 0 A4 = −6.80311E−05 A6 = 7.56313E−06A8 = −2.12005E−07 Zoom data When D0 (distance from object up to 1stsurface) is ∞ wide-angle end intermediate telephoto end Focal length 613.699 18.001 FNO. 2.86 4.73 5.67 D7 0.8 8.09 9.84 D11 10.43 3.15 1.4D12 10.04 3.3 1.2 D15 1.2 10.47 12.94 D17 1.24 1.79 2.81 D19 4.97 1.890.5 D23 1.36 1.36 1.36

SECOND EMBODIMENT

FIG. 3 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a second embodiment ofthe present invention.

FIG. 4A, FIG. 4B, and FIG. 4C are diagrams showing spherical aberration,the astigmatism, the distortion, and the chromatic aberration ofmagnification at the time of the infinite object point focusing of thezoom lens according to the second embodiment of the present invention,where, FIG. 4A shows the state at the wide angle end, FIG. 4B shows theintermediate state, and Fig. C shows the state at the telephoto end.

The zoom lens of the second embodiment, as shown in FIG. 3, has a firstlens group G1, a second lens group G2, an aperture stop S, a third lensgroup G3, a fourth lens group G4, and a fifth lens group G5 in thisorder from the object side. In the diagram, LPF is a low-pass filter, CGis a cover glass, and I is an image pickup surface of an electronicimage pickup element. The first lens group G1 includes a negativemeniscus lens L111 having a convex surface directed toward the objectside, a prism L112, and a cemented lens which is formed by a negativemeniscus lens L113 having a convex surface directed toward the objectside, and a biconvex lens L114, and has a positive refracting power as awhole.

The second lens group G2 includes a biconcave lens L121, and a positivemeniscus lens L122 having a convex surface directed toward the objectside, and has a negative refracting power as a whole. The third lensgroup G3 includes a cemented lens which is formed by a biconvex lensL131 and a biconcave lens L132, and has a positive refracting power as awhole.

The fourth lens group G4 includes a negative meniscus lens L141 having aconvex surface directed toward the object side, and has a negativerefracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has apositive refracting power as a whole.

At the time of zooming from the wide-angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward theimage side, the aperture stop S is fixed, the third lens group G3 movestoward the object side, the fourth lens group G4 moves once toward theimage side, and then moves toward the object side, and the fifth lensgroup G5 moves toward the image side.

An aspheric surface is provided on the surface toward the object side,of the negative meniscus lens 113 having the convex surface directedtoward the object side in the first lens group G1, both surfaces of thebiconcave lens L121 in the second lens group G2, the surface toward theobject side, of the biconvex lens L131, and the surface toward the imageside of the biconcave lens L132 in the third lens group G3, and thesurface toward the object side, of the biconvex lens L142 in the fifthlens group G5.

Next, numerical data of the second embodiment will be enumerated.

Numerical data 2 r1 = 26.407 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 10.001d2 = 2.9 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 =20.270 d5 = 0.1 Nd5 = 1.42001 νd5 = 6.55 (Aspheric surface) r6 = 16.892d6 = 3.54 Nd6 = 1.7495 νd6 = 35.28 r7 = −44.948 d7 = D7 r8 = −73.431 d8= 0.8 Nd8 = 1.8061 νd8 = 40.92 (Aspheric surface) r9 = 5.401 d9 = 0.7(Aspheric surface) r10 = 7.514 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11= 96.185 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 8.347 d13 = 6.32Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −9.655 d14 = 1 Nd14= 1.84666 νd14 = 23.78 r15 = 48.501 d15 = D15 (Aspheric surface) r16 =24.743 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 9.363 d17 = D17 r18 =10.583 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 =−192.596 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 =D23 Aspherical coefficients  5th surface k = 0 A4 = 1.03451E−05 A6 =1.59102E−07 A8 = 0  8th surface k = 0 A4 = 1.43925E−04 A6 = −4.39610E−06A8 = 1.83409E−07  9th surface k = 0 A4 = −3.47884E−04 A6 = −1.24823E−05A8 = −1.16714E−07 13th surface k = 0 A4 = 7.96498E−05 A6 = 1.77836E−06A8 = 2.35088E−08 15th surface k = 0 A4 = 5.27749E−04 A6 = 1.10798E−05 A8= 3.25369E−07 18th surface k = 0 A4 = −8.84149E−05 A6 = 9.05232E−06 A8 =−2.49918E−07 Zoom data When D0 (distance from object up to 1st surface)is ∞ wide-angle end intermediate telephoto end Focal length 6.001 13.717.999 FNO. 2.86 4.73 5.67 D7 0.8 6.41 7.83 D11 8.43 2.82 1.4 D12 11.223.58 1.2 D15 1.2 11.62 14.83 D17 1.19 1.64 2.05 D19 4.98 1.74 0.5 D231.36 1.36 1.36

THIRD EMBODIMENT

FIG. 5 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a third embodiment.

FIG. 6A, FIG. 6B, and FIG. 6C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the third embodiment, where, FIG.6A shows the state at the wide angle end, FIG. 6B shows the intermediatestate, and FIG. 6C shows the state at the telephoto end.

The zoom lens of the third embodiment, as shown in FIG. 5, has a firstlens group G1, a second lens group G2, an aperture stop S, a third lensgroup G3, a fourth lens group G4, and a fifth lens group G5 in thisorder from the object side. In the diagram, LPF is a low-pass filter, CGis a cover glass, and I is an image pickup surface of an electronicimage pickup element.

The first lens group G1 includes a negative meniscus lens L111 having aconvex surface directed toward an object side, a prism 112, and acemented lens which is formed by a negative meniscus lens L113 having aconvex surface directed toward the object side, and a biconvex lensL114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121, and a positivemeniscus lens L122 having a convex surface directed toward the objectside, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconvex lens L131 and a biconcave lens L132, and has a positiverefracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having aconvex surface directed toward the object side, and has a negativerefracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has apositive refracting power as a whole.

At the time of zooming from the wide-angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward theimage side, the aperture stop S is fixed, the third lens group G3 movestoward the object side, the fourth lens group G4 moves once toward theimage side, and then moves toward the object side, and the fifth lensgroup G5 moves toward the image side.

An aspheric surface is provided on the surface toward the object side,of the negative meniscus lens L113 having the convex surface directedtoward the object side in the first lens group G1, both surfaces of thebiconcave lens L121 in the second lens group G2, the surface toward theobject side, of the biconvex lens L131, and the surface toward the imageside of the biconcave lens L132 in the third lens group G3, and thesurface toward the object side, of the biconvex lens L142 in the fifthlens group G5.

Next, numerical data of the third embodiment will be enumerated.

Numerical data 3 r1 = 27.82 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 10.002d2 = 2.9 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 =23.480 d5 = 0.1 Nd5 = 1.51824 νd5 = 12.85 (Aspheric surface) r6 = 19.567d6 = 3.54 Nd6 = 1.741 νd6 = 52.64 r7 = −28.65 d7 = D7 r8 = −61.821 d8 =0.8 Nd8 = 1.8061 νd8 = 40.92 (Aspheric surface) r9 = 4.913 d9 = 0.7(Aspheric surface) r10 = 6.827 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11= 132.993 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 8.583 d13 = 8.63Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −8.089 d14 = 1 Nd14= 1.84666 νd14 = 23.78 r15 = 48.417 d15 = D15 (Aspheric surface) r16 =35.107 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 10.292 d17 = D17 r18= 9.475 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 =−233.568 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 =D23 Aspherical coefficients  5th surface k = 0 A4 = 2.38481E−06 A6 =1.42255E−07 A8 = 0  8th surface k = 0 A4 = 2.60205E−04 A6 = −1.86315E−05A8 = 3.96540E−07  9th surface k = 0 A4 = −3.29150E−04 A6 = −3.05243E−05A8 = −1.10959E−06 13th surface k = 0 A4 = 3.14928E−05 A6 = −1.15481E−06A8 = 2.01049E−08 15th surface k = 0 A4 = 4.73717E−04 A6 = 1.67097E−05 A8= −3.53306E−07 18th surface k = 0 A4 = −9.35376E−05 A6 = 5.96154E−06 A8= −1.74283E−07 Zoom data When D0 (distance from object up to 1stsurface) is ∞ wide-angle end intermediate telephoto end Focal length 613.7 17.998 FNO. 2.86 4.73 5.67 D7 0.8 7.81 9.62 D11 10.22 3.22 1.4 D129.02 3.17 1.2 D15 1.2 10.49 12.72 D17 1.68 0.85 1.59 D19 4.1 1.51 0.49D23 1.36 1.36 1.36

FOURTH EMBODIMENT

FIG. 7 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a fourth embodiment ofthe present invention.

FIG. 8A, FIG. 8B, and FIG. 8C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the fourth embodiment, where,FIG. 8A shows the state at the wide angle end, FIG. 8B shows theintermediate state, and FIG. 8C shows the state at the telephoto end.

The zoom lens of the fourth embodiment, as shown in FIG. 7, has a firstlens group G1, a second lens group G2, an aperture stop S, a third lensgroup G3, a fourth lens group G4, and a fifth lens group G5 in thisorder from an object side. In the diagram, LPF is a low-pas filter, CGis a cover glass, and I is an image pickup surface of an electronicimage pickup element.

The first lens group G1 includes a negative meniscus lens L111 having aconvex surface directed toward the object side, a prism L112, and acemented lens which is formed by a negative meniscus lens L113 having aconvex surface directed toward the object side, and a biconvex lensL114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121, and a positivemeniscus lens L122 having a convex surface directed toward the objectside, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconvex lens L131 and a biconcave lens L132, and has a positiverefracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having aconvex surface directed toward the object side, and has a negativerefracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has apositive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward theimage side, the aperture stop S is fixed, the third lens group G3 movestoward the object side, the fourth lens group G4 moves once toward theimage side, and then moves toward the object side, and the fifth lensgroup G5 moves toward the image side.

An aspheric surface is provided on the surface toward the object side,of the negative meniscus lens L113 having the convex surface directedtoward the object side in the first lens group G1, both surfaces of thebiconcave lens L121 in the second lens group G2, the surface toward theobject side of the biconvex lens L131, and the surface toward the imageside of the biconcave lens L132 in the third lens group G3, and thesurface toward the object side, of the biconvex lens L142 in the fifthlens group G5.

Next, numerical data of the fourth embodiment will be enumerated.

Numerical data 4 r1 = 27.694 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 10.006d2 = 2.9 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 =19.683 d5 = 0.1 Nd5 = 1.54856 νd5 = 7.04 (Aspheric surface) r6 = 17.419d6 = 3.54 Nd6 = 1.883 νd6 = 40.76 r7 = −93.913 d7 = D7 r8 = −71.447 d8 =0.8 Nd8 = 1.8061 νd8 = 40.92 (Aspheric surface) r9 = 5.388 d9 = 0.7(Aspheric surface) r10 = 7.37 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11 =95.844 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 8.478 d13 = 6.45Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −10.197 d14 = 1 Nd14= 1.84666 νd14 = 23.78 r15 = 51.863 d15 = D15 (Aspheric surface) r16 =24.22 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 9.369 d17 = D17 r18 =10.688 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 =−170.684 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 =D23 Aspherical coefficients  5th surface k = 0 A4 = 1.89634E−05 A6 =2.52746E−08 A8 = 0.00000E+00  8th surface k = 0 A4 = 4.32026E−04 A6 =−1.73558E−05 A8 = 2.97589E−07  9th surface k = 0 A4 = 2.83249E−05 A6 =−2.70770E−05 A8 = −3.90203E−07 13th surface k = 0 A4 = 6.36673E−05 A6 =2.41615E−06 A8 = −1.70207E−08 15th surface k = 0 A4 = 4.36864E−04 A6 =1.97436E−05 A8 = −1.21544E−07 18th surface k = 0 A4 = −1.13296E−04 A6 =1.04349E−05 A8 = −2.67157E−07 Zoom data When D0 (distance from object upto 1st surface) is ∞ wide-angle end intermediate telephoto end Focallength 6.004 13.7 17.999 FNO. 2.84 4.7 5.63 D7 0.8 6.81 8.42 D11 9.023.01 1.4 D12 10.81 3.55 1.2 D15 1.2 11.71 13.72 D17 1.39 1.6 2.82 D194.84 1.38 0.5 D23 1.36 1.36 1.36

FIFTH EMBODIMENT

FIG. 9 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a fifth embodiment of thepresent invention.

FIG. 10A, FIG. 10B, and FIG. 10C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the fifth embodiment, where, FIG.10A shows the state at the wide angle end, FIG. 10B shows theintermediate state, and FIG. 10C shows the state at the telephoto end.

The zoom lens of the fifth embodiment, as shown in FIG. 9, has a firstlens group G1, a second lens group G2, an aperture stop S, a third lensgroup G3, a fourth lens group G4, and a fifth lens group G5, in thisorder from an object side. In the diagram, LPF is a low-pass filter, CGis a cover glass, and I is an image pickup surface of an electronicimage pickup element.

The first lens group G1 includes a negative meniscus lens L111 having aconvex surface directed toward the object side, a prism L112, andcemented lens which is formed by a negative meniscus lens L113 having aconvex surface directed toward the object side, and a biconvex lensL114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121, and a positivemeniscus lens L122 having a convex surface directed toward the objectside, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconvex lens L131 and a biconcave lens L132, and has a positiverefracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having aconvex surface directed toward the object side, and has a negativerefracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has apositive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward theimage side, the aperture stop S is fixed, the third lens group G3 movestoward the object side, the fourth lens group G4 moves once toward theimage side, and then moves toward the object side, and the fifth lensgroup G5 moves toward the image side.

An aspheric surface is provided on a surface toward the object side, ofthe negative meniscus lens L113 having the convex surface directedtoward the object side in the first lens group G1, both surfaces of thebiconcave lens L121 in the second lens group G2, the surface toward theobject side of the biconvex lens L131, and the surface toward the imageside of the biconcave lens L132 in the third lens group G3, and thesurface toward the object side, of the biconvex lens L142 in the fifthlens group G5.

Next, numerical data of the fifth embodiment will be enumerated.

Numerical data 5 r1 = 26.268 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 9.767d2 = 2.9 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 =18.845 d5 = 0.1 Nd5 = 1.65228 νd5 = 12.75 (Aspheric surface) r6 = 17.425d6 = 3.54 Nd6 = 1.741 νd6 = 52.64 r7 = −46.982 d7 = D7 r8 = −47.767 d8 =0.8 Nd8 = 1.8061 νd8 = 40.92 (Aspheric surface) r9 = 5.610 d9 = 0.7(Aspheric surface) r10 = 7.861 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11= 651.723 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 8.372 d13 = 6.59Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −10.413 d14 = 1 Nd14= 1.84666 νd14 = 23.78 r15 = 47.183 d15 = D15 (Aspheric surface) r16 =19.829 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 9.344 d17 = D17 r18 =11.290 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 =−3235.664 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 =∞ d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 =D23 Aspherical coefficients  5th surface k = 0 A4 = 1.29265E−05 A6 =2.25482E−08 A8 = 0  8th surface k = 0 A4 = 3.13232E−04 A6 = −1.10497E−05A8 = 2.00754E−07  9th surface k = 0 A4 = −1.49920E−04 A6 = −1.69745E−05A8 = −3.47629E−07 13th surface k = 0 A4 = 6.03004E−05 A6 = 1.94139E−06A8 = 1.57565E−08 15th surface k = 0 A4 = 5.14589E−04 A6 = 9.41419E−06 A8= 4.95331E−07 18th surface k = 0 A4 = −8.99715E−05 A6 = 8.05337E−06 A8 =−1.55937E−07 Zoom data When D0 (distance from object up to 1st surface)is ∞ wide-angle end intermediate telephoto end Focal length 6.1 13.4217.995 FNO. 3.15 4.79 5.87 D7 1.44 7.29 8.68 D11 12.19 3.52 1.54 D127.82 3.25 0.84 D15 1.21 11.41 13.88 D17 1.42 1.6 2.93 D19 4.82 1.38 0.4D23 1.36 1.36 1.36

SIXTH EMBODIMENT

FIG. 11 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a sixth embodiment of thepresent invention.

FIG. 12A, FIG. 12B, and FIG. 12C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the sixth embodiment, where, FIG.12A shows the state at the wide angle end, FIG. 12B shows theintermediate state, and FIG. 12C shows the state at the telephoto end.

The zoom lens of the sixth embodiment, as shown in FIG. 11, has a firstlens group G1, a second lens group G2, an aperture stop S, a third lensgroup G3, a fourth lens group G4, and a fifth lens group G5, in thisorder from an object side. In the diagram, LPF is a low-pass filter, CGis a cover glass, and I is an image pickup surface of an electronicimage pickup element.

The first lens group G1 includes a negative meniscus lens L111 having aconvex surface directed toward the object side, a prism L112, and acemented lens which is formed by a negative meniscus lens L113 having aconvex surface directed toward the object side, and a biconvex lensL114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121, and a positivemeniscus lens L122 having a convex surface directed toward the objectside, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconvex lens L131 and a biconcave lens L132, and has a positiverefracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having aconvex surface directed toward the object side, and has a negativerefracting power as a whole.

The fifth lens group G5 includes a positive meniscus lens L142 having aconvex surface directed toward the object side, and has positiverefracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward theimage side, the aperture stop S is fixed, the third lens group G3 movestoward the object side, the fourth lens group G4 moves once toward theimage side, and then moves toward the object side, and the fifth lensgroup G5 moves toward the image side.

An aspheric surface is provided on the surface toward the object side,of the negative meniscus lens L113 having the convex surface directedtoward the object side in the first lens group G1, both surfaces of thebiconcave lens L121 in the second lens group G2, the surface toward theobject side of the biconvex lens L131, and the surface toward the imageside of the biconcave lens L132 in the third lens group G3, and thesurface toward the object side, of the positive meniscus lens L142having the convex surface directed toward the object side in the fifthlens group G5.

Next, numerical data of the sixth embodiment will be enumerated.

Numerical data 6 r1 = 23.104 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 9.993d2 = 2.9 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 =144.417 d5 = 0.1 Nd5 = 1.59885 νd5 = 6.52 (Aspheric surface) r6 =120.347 d6 = 3.54 Nd6 = 1.741 νd6 = 52.64 r7 = −15.632 d7 = D7 r8 =−67.973 d8 = 0.8 Nd8 = 1.8061 νd8 = 40.92 (Aspheric surface) r9 = 5.079d9 = 0.7 (Aspheric surface) r10 = 7.029 d10 = 2.2 Nd10 = 1.7552 νd10 =27.51 r11 = 101.993 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 7.719d13 = 6.28 Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −9.571d14 = 1 Nd14 = 1.84666 νd14 = 23.78 r15 = 34.509 d15 = D15 (Asphericsurface) r16 = 39.476 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 9.117d17 = D17 r18 = 7.840 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Asphericsurface) r19 = 34.132 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 =62.84 r21 = ∞ d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14r23 = ∞ d23 = D23 Aspherical coefficients  5th surface k = 0 A4 =−4.37427E−05 A6 = 4.88599E−07 A8 = 0  8th surface k = 0 A4 =−4.24746E−04 A6 = 1.70408E−05 A8 = −5.77793E−07  9th surface k = 0 A4 =−1.15464E−03 A6 = 3.78562E−05 A8 = −3.07050E−06 13th surface k = 0 A4 =1.41938E−04 A6 = −5.92299E−07 A8 = 7.51323E−08 15th surface k = 0 A4 =9.41257E−04 A6 = −6.26116E−06 A8 = 1.51062E−06 18th surface k = 0 A4 =−7.24351E−05 A6 = −2.74136E−07 A8 = −7.56639E−08 Zoom data When D0(distance from object up to 1st surface) is ∞ wide-angle endintermediate telephoto end Focal length 6.005 13.7 17.999 FNO. 3.01 4.935.95 D7 0.8 6.91 8.38 D11 8.98 2.86 1.4 D12 10.51 3.71 1.2 D15 1.2 11.5613.88 D17 1.59 1.78 2.67 D19 4.97 1.21 0.5 D23 1.36 1.36 1.36

SEVENTH EMBODIMENT

FIG. 13 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a seventh embodiment ofthe present invention.

FIG. 14A, FIG. 14B, and FIG. 14C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the seventh embodiment, where,FIG. 14A shows the state at the wide angle end, FIG. 14B shows theintermediate state, and FIG. 14C shows the state at the telephoto end.

The zoom lens of the seventh embodiment, as shown in FIG. 13, has afirst lens group G1, a second lens group G2, an aperture stop S, a thirdlens group G3, a fourth lens group G4, and a fifth lens group G5 in thisorder from an object side. In the diagram, LPF is a low-pass filter, CGis a cover glass, and I is an image pickup surface of an electronicimage pickup element.

The first lens group G1 includes a negative meniscus lens L111 having aconvex surface directed toward the object side, a prism L112, and acemented lens which is formed by a negative meniscus lens L113 having aconvex surface directed toward the object side, and a biconvex lensL114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121, and a positivemeniscus lens L122 having a convex surface directed toward the objectside, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconvex lens L131 and a biconcave lens L132, and has a positiverefracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having aconvex surface directed toward the object side, and has a negativerefracting power as a whole.

The fifth lens group G5 includes a positive meniscus lens L142 having aconvex surface directed toward the object side, and has a positiverefracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward theimage side, the aperture stop S is fixed, the third lens group G3 movestoward the object side, the fourth lens group G4 moves once toward theimage side, and then moves toward the object side, and the fifth lensgroup G5 moves toward the image side.

An aspheric surface is provided on the surface toward the object side,of the negative meniscus lens L113 having the convex surface directedtoward the object side in the first lens group G1, both surfaces of thebiconcave lens L121 in the second lens group G2, the surface toward theobject side of the biconvex lens L131, and the surface toward the imageside of the biconcave lens L132 in the third lens group G3, and thesurface toward the object side, of the positive meniscus lens L142having the convex surface directed toward the object side in the fifthlens group G5.

Next, numerical data of the seventh embodiment will be enumerated.

Numerical data 7 r1 = 23.339 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 9.998d2 = 2.9 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 =100.200 d5 = 0.1 Nd5 = 1.79525 νd5 = 9.95 (Aspheric surface) r6 = 83.501d6 = 3.54 Nd6 = 1.741 νd6 = 52.64 r7 = −16.063 d7 = D7 r8 = −45.653 d8 =0.8 Nd8 = 1.8061 νd8 = 40.92 (Aspheric surface) r9 = 5.378 d9 = 0.7(Aspheric surface) r10 = 7.441 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11= 202.84 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 7.519 d13 = 6.32Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −10.334 d14 = 1 Nd14= 1.84666 νd14 = 23.78 r15 = 26.284 d15 = D15 (Aspheric surface) r16 =28.574 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 8.89 d17 = D17 r18 =7.764 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 =32.431 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 =D23 Aspherical coefficients  5th surface k = 0 A4 = −2.65536E−05 A6 =3.17647E−07 A8 = 0  8th surface k = 0 A4 = −3.26054E−04 A6 = 1.26273E−05A8 = −4.63097E−07  9th surface k = 0 A4 = −9.57291E−04 A6 = 2.85872E−05A8 = −2.27299E−06 13th surface k = 0 A4 = 1.05906E−04 A6 = 3.76011E−07A8 = 3.75282E−08 15th surface k = 0 A4 = 9.47239E−04 A6 = −1.75798E−06A8 = 1.62992E−06 18th surface k = 0 A4 = −8.98935E−05 A6 = 9.26013E−07A8 = −9.48654E−08 Zoom data When D0 (distance from object up to 1stsurface) is ∞ wide-angle end intermediate telephoto end Focal length6.001 13.7 18 FNO. 3.01 4.93 5.92 D7 0.8 6.87 8.47 D11 9.07 3 1.4 D1210.55 3.61 1.2 D15 1.2 11.39 13.85 D17 1.66 1.82 2.52 D19 4.66 1.26 0.5D23 1.36 1.36 1.36

EIGHTH EMBODIMENT

FIG. 15 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to an eighth embodiment ofthe present invention.

FIG. 16A, FIG. 16B, and FIG. 16C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the eighth embodiment, where,FIG. 16A shows the state at the wide angle end, FIG. 16B shows theintermediate state, and FIG. 16C shows the state at the telephoto end.

The zoom lens of the eighth embodiment, as shown in FIG. 15, has a firstlens group G1, a second lens group G2, an aperture stop S, a third lensgroup G3, a fourth lens group G4, and a fifth lens group G5 in thisorder from an object side. In the diagram, LPF is a low-pas filter, CGis a cover glass, and I is an image pickup surface of an electronicimage pickup element.

The first lens group G1 includes a negative meniscus lens L111 having aconvex surface directed toward the object side, a prism L112, and acemented lens which is formed by a negative meniscus lens L113 having aconvex surface directed toward the object side, and a biconvex lensL114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121, and a positivemeniscus lens L122 having a convex surface directed toward the objectside, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconvex lens L131 and a biconcave lens L132, and has a positiverefracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having aconvex surface directed toward the object side, and has a negativerefracting power as a whole.

The fifth lens group G5 includes a positive meniscus lens L142 having aconvex surface directed toward the object side, and has the positiverefracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward animage side, the aperture stop S is fixed, the third lens group G3 movestoward the object side, the fourth lens group G4 moves once toward theimage side, and then moves toward the object side, and the fifth lensgroup G5 moves toward the image side.

An aspheric surface is provided on the surface toward the object side,of the negative meniscus lens L113 having the convex surface directedtoward the object side in the first lens group G1, both surfaces of thebiconcave lens L121 in the second lens group G2, a surface toward theobject side of the biconvex lens L131, and a surface toward the imageside of the biconcave lens L132 in the third lens group G3, and thesurface toward the object side, of the positive meniscus lens L142having the convex surface directed toward the object side in the fifthlens group G5.

Next, numerical data of the eighth embodiment will be enumerated.

Numerical data 8 r1 = 23.412 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 9.999d2 = 2.9 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 =71.727 d5 = 0.1 Nd5 = 1.9712 νd5 = 12.88 (Aspheric surface) r6 = 59.773d6 = 3.54 Nd6 = 1.741 νd6 = 52.64 r7 = −16.653 d7 = D7 r8 = −36.331 d8 =0.8 Nd8 = 1.8061 νd8 = 40.92 (Aspheric surface) r9 = 5.425 d9 = 0.7(Aspheric surface) r10 = 7.528 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11= 1523.438 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 7.312 d13 =6.35 Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −10.511 d14 = 1Nd14 = 1.84666 νd14 = 23.78 r15 = 22.264 d15 = D15 (Aspheric surface)r16 = 31.087 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 9.171 d17 = D17r18 = 7.719 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19= 34.976 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 =D23 Aspherical coefficients  5th surface k = 0 A4 = −1.63140E−05 A6 =2.12684E−07 A8 = 0  8th surface k = 0 A4 = −1.88552E−04 A6 = 7.75646E−06A8 = −3.54924E−07  9th surface k = 0 A4 = −8.03970E−04 A6 = 2.18772E−05A8 = −2.04118E−06 13th surface k = 0 A4 = 8.46048E−05 A6 = 8.81547E−07A8 = 1.40013E−08 15th surface k = 0 A4 = 9.97088E−04 A6 = 1.26510E−06 A8= 1.91272E−06 18th surface k = 0 A4 = −1.04269E−04 A6 = 9.09683E−07 A8 =−9.18645E−08 Zoom data When D0 (distance from object up to 1st surface)is ∞ wide-angle end intermediate telephoto end Focal length 6.001 13.718 FNO. 3.02 4.95 5.89 D7 0.8 6.83 8.53 D11 9.13 3.11 1.4 D12 10.31 3.471.2 D15 1.2 11.21 13.79 D17 1.84 1.82 2.3 D19 4.44 1.28 0.5 D23 1.361.36 1.36

NINTH EMBODIMENT

FIG. 17 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a ninth embodiment of thepresent invention.

FIG. 18A, FIG. 18B, and FIG. 18C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the ninth embodiment, where, FIG.18A shows the state at the wide angle end, FIG. 18B shows theintermediate state, and FIG. 18C shows the state at the telephoto end.

The zoom lens of the ninth embodiment, as shown in FIG. 17, has a firstlens group G1, a second lens group G2, an aperture stop S, a third lensgroup G3, a fourth lens group G4, and a fifth lens group G5, in thisorder from the object side. In the diagram, LPF is a low-pass filter, CGis a cover glass, and I is an image pickup surface of an electronicimage pickup element.

The first lens group G1 includes negative meniscus lens L111 having aconvex surface directed toward the object side, a prism L112, and acemented lens which is formed by a negative meniscus lens L113 having aconvex surface directed toward the object side, and a biconvex lensL114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121, and a positivemeniscus lens L122 having a convex surface directed toward the objectside, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconvex lens L131 and a biconcave lens L132, and has a positiverefracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having aconvex surface directed toward the object side, and has a negativerefracting power as a whole.

The fifth lens group. G5 includes a positive meniscus lens L142 having aconvex surface directed toward the object side, and has a positiverefracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward animage side, the aperture stop S is fixed, the third lens group G3 movestoward the object side, the fourth lens group G4 moves once toward theimage side, and then moves toward the object side, and the fifth lensgroup G5 moves toward the image side.

An aspheric surface is provided on the surface toward the object side,of the negative meniscus lens L113 having the convex surface directedtoward the object side in the first lens group G1, both surfaces of thebiconcave lens L121 in the second lens group G2, a surface toward theobject side of the biconvex lens L131, and a surface toward the imageside of the biconcave lens L132 in the third lens group G3, and thesurface toward the object side of the positive meniscus lens L142 havingthe convex surface directed toward the object side in the fifth lensgroup G5.

Next, numerical data of the ninth embodiment will be enumerated.

Numerical data 9 r1 = 22.766 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 9.996d2 = 2.9 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 =201.902 d5 = 0.1 Nd5 = 2.05122 νd5 = 6.28 (Aspheric surface) r6 =168.251 d6 = 3.54 Nd6 = 1.741 νd6 = 52.64 r7 = −15.092 d7 = D7 r8 =−33.130 d8 = 0.8 Nd8 = 1.8061 νd8 = 40.92 (Aspheric surface) r9 = 5.469d9 = 0.7 (Aspheric surface) r10 = 7.619 d10 = 2.2 Nd10 = 1.7552 νd10 =27.51 r11 = −366.416 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 7.087d13 = 6.41 Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −10.191d14 = 1 Nd14 = 1.84666 νd14 = 23.78 r15 = 19.545 d15 = D15 (Asphericsurface) r16 = 53.254 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 9.799d17 = D17 r18 = 7.635 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Asphericsurface) r19 = 39.242 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 =62.84 r21 = ∞ d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14r23 = ∞ d23 = D23 Aspherical coefficients  5th surface k = 0 A4 =−2.29550E−05 A6 = 1.93244E−07 A8 = 0  8th surface k = 0 A4 =−2.64173E−04 A6 = 1.12898E−05 A8 = −4.80203E−07  9th surface k = 0 A4 =−8.96070E−04 A6 = 2.86426E−05 A8 = −2.27403E−06 13th surface k = 0 A4 =8.06718E−05 A6 = 3.66237E−07 A8 = 1.49391E−08 15th surface k = 0 A4 =1.14232E−03 A6 = −2.15240E−06 A8 = 2.64820E−06 18th surface k = 0 A4 =−1.11897E−04 A6 = −1.49140E−07 A8 = −8.03112E−08 Zoom data When D0(distance from object up to 1st surface) is ∞ wide-angle endintermediate telephoto end Focal length 6.004 13.7 17.999 FNO. 3.05 5.035.99 D7 0.8 6.83 8.58 D11 9.18 3.14 1.4 D12 10.28 3.48 1.2 D15 1.2 11.1513.77 D17 1.8 1.81 2.19 D19 4.37 1.22 0.5 D23 1.36 1.36 1.36

TENTH EMBODIMENT

FIG. 19 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a tenth embodiment of thepresent invention.

FIG. 20A, FIG. 20B, and FIG. 20C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the tenth embodiment, where, FIG.20A shows the state at the wide angle end, FIG. 20B shows theintermediate state, and FIG. 20C shows the state at the telephoto end.

The zoom lens of the tenth embodiment, as shown in FIG. 19, has a firstlens group G1, a second lens group G2, an aperture stop S, a third lensgroup G3, and a fourth lens group G4 in this order from the object side.In the diagram, LPF is a low-pass filter, CG is a cover glass, and I isan image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having aconvex surface directed toward the object side, a prism L212, and acemented lens which is formed by a positive meniscus lens L213 having aconvex surface directed toward an image side and a biconcave lens L214,and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by abiconvex lens L221 and a negative meniscus lens L222 having a convexsurface directed toward the image side, and has a positive refractingpower as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconcave lens L231 and a positive meniscus lens L232 having a convexside directed toward the object side, and has a negative refractingpower as a whole.

The fourth lens group G4 includes a cemented lens which is formed by abiconvex lens L241 and a negative meniscus lens L242 having a concavesurface directed toward the object side, and has a positive refractingpower as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward theobject side, the aperture stop S is fixed, the third lens group G3 movestoward the image side, and the fourth lens group G4 moves toward theimage side.

An aspheric surface is provided on a surface toward the object side, ofthe positive meniscus lens L213 having the convex surface directedtoward the image side in the first lens group G1, a surface on theobject side of the biconvex lens L221, and a surface on the image sideof the negative meniscus lens having the convex surface directed towardthe image side in the second lens group G2, and a surface on the objectside of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the tenth embodiment will be enumerated.

Numerical data 10 r1 = 16.18 d1 = 1.1 Nd1 = 1.741 νd1 = 52.64 r2 = 8.095d2 = 3.7 r3 = ∞ d3 = 12.5 Nd3 = 1.801 νd3 = 34.97 r4 = ∞ d4 = 0.55 r5 =−31.723 d5 = 2.2 Nd5 = 1.8061 νd5 = 40.92 (Aspheric surface) r6 = −8.755d6 = 0.7 Nd6 = 1.51633 νd6 = 64.14 r7 = 18.545 d7 = D7 r8 = 9.850 d8 = 4Nd8 = 1.43875 νd8 = 94.93 (Aspheric surface) r9 = −12 d9 = 0.35 Nd9 =1.41244 νd9 = 12.42 r10 = −15.504 d10 = D10 (Aspheric surface) r11 =Aperture stop d11 = D11 r12 = −16.407 d12 = 0.7 Nd12 = 1.497 νd12 =81.54 r13 = 18.799 d13 = 1.6 Nd13 = 1.84666 νd13 = 23.78 r14 = 30.356d14 = D14 r15 = 15.129 d15 = 3.5 Nd15 = 1.7432 νd15 = 49.34 (Asphericsurface) r16 = −6 d16 = 0.7 Nd16 = 1.80518 νd16 = 25.42 r17 = −17.077d17 = D17 r18 = ∞ d18 = 1.44 Nd18 = 1.54771 νd18 = 62.84 r19 = ∞ d19 =0.8 r20 = ∞ d20 = 0.6 Nd20 = 1.51633 νd20 = 64.14 r21 = ∞ d21 = D21Aspherical coefficients  5th surface k = 0 A4 = 4.47180E−05 A6 =−2.1758E−07 A8 = 0  8th surface k = 0 A4 = −2.23159E−04 A6 =−1.95685E−06 A8 = 0.00000E+00 10th surface k = 0 A4 = 5.19411E−05 A6 =−1.17193E−06 A8 = 0.00000E+00 15th surface k = 0 A4 = −1.16950E−04 A6 =−4.73116E−07 A8 = 0.00000E+00 Zoom data When D0 (distance from object upto 1st surface) is ∞ wide-angle end intermediate telephoto end Focallength 6.077 13.7 17.98 FNO. 2.85 3.41 3.73 D7 12.35 4.54 0.8 D10 1.599.4 13.14 D11 1.4 6.41 10.76 D14 8.19 7.01 2.99 D17 5.4 1.58 1.25 D211.36 1.36 1.36

ELEVENTH EMBODIMENT

FIG. 21 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to an eleventh embodiment ofthe present invention.

FIG. 22A, FIG. 22B, and FIG. 22C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the eleventh embodiment, where,FIG. 22A shows the state at the wide angle end, FIG. 22B shows theintermediate state, and FIG. 22C shows the state at the telephoto end.

The zoom lens of the eleventh embodiment, as shown in FIG. 21, has afirst lens group G1, a second lens group G2, an aperture stop S, a thirdlens group G3, and a fourth lens group G4 in this order from the objectside. In the diagram, LPF is a low-pass filter, CG is a cover glass, andI is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having aconvex surface directed toward the object side, a prism L212, and acemented lens which is formed by a biconvex lens L213 and a biconcavelens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by abiconvex lens L221 and a negative meniscus lens L222 having a convexsurface directed toward an image side, and has a positive refractingpower as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconcave lens L231 and a positive meniscus lens L232 having a convexsurface directed toward the object side, and has a negative refractingpower as a whole.

The fourth lens group G4 includes a cemented lens which is formed by abiconvex lens L241 and a negative meniscus lens L242 having a concavesurface directed toward the object side, and has a positive refractingpower as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward theobject side, the aperture stop S is fixed, the third lens group G3 movestoward the image side, and the fourth lens group G4 moves toward theimage side.

An aspheric surface is provided on a surface toward the object side, ofthe biconvex lens L213 in the first lens group G1, a surface on theobject side of the biconvex lens L221, and a surface on the image sideof the negative meniscus lens L222 having the convex surface directedtoward the image side in the second lens group G2, and a surface on theobject side of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the eleventh embodiment will be enumerated.

Numerical data 11 r1 = 48.381 d1 = 1.1 Nd1 = 1.7432 νd1 = 49.34 r2 =10.569 d2 = 3 r3 = ∞ d3 = 12.5 Nd3 = 1.801 νd3 = 34.97 r4 = ∞ d4 = 0.4r5 = 94.633 d5 = 1.97 Nd5 = 1.8061 νd5 = 40.92 (Aspheric surface) r6 =−12.45 d6 = 0.7 Nd6 = 1.52 νd6 = 57 r7 = 19.015 d7 = D7 r8 = 12.682 d8 =6.23 Nd8 = 1.497 νd8 = 81.54 (Aspheric surface) r9 = −24.282 d9 = 0.35Nd9 = 1.42001 νd9 = 6.55 r10 = −30.780 d10 = D10 (Aspheric surface) r11= Aperture stop d11 = D11 r12 = −13.223 d12 = 0.7 Nd12 = 1.48749 νd12 =70.23 r13 = 8.748 d13 = 1.6 Nd13 = 1.83481 νd13 = 40.7 r14 = 19.455 d14= D14 r15 = 12.231 d15 = 3.5 Nd15 = 1.7432 νd15 = 49.34 (Asphericsurface) r16 = −6 d16 = 0.7 Nd16 = 1.84666 νd16 = 23.78 r17 = −16.336d17 = D17 r18 = ∞ d18 = 1.44 Nd18 = 1.54771 νd18 = 62.84 r19 = ∞ d19 =0.8 r20 = ∞ d20 = 0.6 Nd20 = 1.51633 νd20 = 64.14 r21 = ∞ d21 = D21Aspherical coefficients  5th surface k = 0 A4 = 1.92293E−05 A6 =−3.35070E−08 A8 = 0  8th surface k = 0 A4 = −7.14678E−05 A6 =−1.27432E−07 A8 = 0.00000E+00 10th surface k = 0 A4 = 1.08454E−05 A6 =1.53862E−07 A8 = 0.00000E+00 15th surface k = 0 A4 = −1.71178E−04 A6 =5.29534E−07 A8 = 0.00000E+00 Zoom data When D0 (distance from object upto 1st surface) is ∞ wide-angle end intermediate telephoto end Focallength 5.99 13.7 17.997 FNO. 2.85 3.49 3.73 D7 15.36 4.85 0.8 D10 1.612.11 16.16 D11 1.4 7.07 9.13 D14 6.31 4.18 3 D17 5.62 2.08 1.21 D211.36 1.36 1.36

TWELFTH EMBODIMENT

FIG. 23 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a twelfth embodiment ofthe present invention.

FIG. 24A, FIG. 24B, and FIG. 24C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the twelfth embodiment, where,FIG. 24A shows the state at the wide angle end, FIG. 24B shows theintermediate state, and FIG. 24C shows the state at the telephoto end.

The zoom lens of the twelfth embodiment, as shown in FIG. 23, has afirst lens group G1, a second lens group G2, an aperture stop S, a thirdlens group G3, and a fourth lens group G4, in this order from an objectside. In the diagram, LPF is a low-pass filter, CG is a cover glass, andI is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having aconvex surface directed toward the object side, a prism L212, and acemented lens which is formed by a positive meniscus lens L213 having aconvex surface directed toward an image side, and a biconcave lens L214,and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by abiconvex lens L221 and a negative meniscus lens L222 having a convexsurface directed toward the image side, and has a positive refractingpower as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconcave lens L231 and a positive meniscus lens L232 having a convexsurface directed toward the object side, and has a negative refractingpower as a whole.

The fourth lens group G4 includes a cemented lens which is formed by abiconvex lens L241 and a negative meniscus lens L242 having a concavesurface directed toward the object side, and has a positive refractingpower as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward theobject side, the aperture stop S is fixed, the third lens group G3 movestoward the image side, and the fourth lens group G4 moves toward theimage side.

An aspheric surface is provided on a surface toward the object side, ofthe positive meniscus lens L213 having the convex surface directedtoward the image side in the first lens group G1, a surface on theobject side of the biconvex lens L221, and a surface on the image sideof the negative meniscus lens L222 having the convex surface directedtoward the image side in the second lens group G2, and a surface on theobject side of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the twelfth embodiment will be enumerated.

Numerical data 12 r1 = 15.958 d1 = 1.1 Nd1 = 1.741 νd1 = 52.64 r2 =8.095 d2 = 3.7 r3 = ∞ d3 = 12.5 Nd3 = 1.801 νd3 = 34.97 r4 = ∞ d4 = 0.55r5 = −29.717 d5 = 2.2 Nd5 = 1.8061 νd5 = 40.92 (Aspheric surface) r6 =−8.846 d6 = 0.7 Nd6 = 1.51633 νd6 = 64.14 r7 = 18.475 d7 = D7 r8 = 9.653d8 = 4 Nd8 = 1.43875 νd8 = 94.93 (Aspheric surface) r9 = −12 d9 = 0.35Nd9 = 1.51824 νd9 = 12.85 r10 = −14.260 d10 = D10 (Aspheric surface) r11= Aperture stop d11 = D11 r12 = −16.685 d12 = 0.7 Nd12 = 1.48749 νd12 =70.23 r13 = 11.863 d13 = 1.6 Nd13 = 1.83481 νd13 = 42.71 r14 = 20.917d14 = D14 r15 = 15.028 d15 = 3.5 Nd15 = 1.7432 νd15 = 49.34 (Asphericsurface) r16 = −6 d16 = 0.7 Nd16 = 1.84666 νd16 = 23.78 r17 = −16.013d17 = D17 r18 = ∞ d18 = 1.44 Nd18 = 1.54771 νd18 = 62.84 r19 = ∞ d19 =0.8 r20 = ∞ d20 = 0.6 Nd20 = 1.51633 νd20 = 64.14 r21 = ∞ d21 = D21Aspherical coefficients  5th surface k = 0 A4 = 4.58748E−05 A6 =2.00925E−08 A8 = 0  8th surface k = 0 A4 = −2.22174E−04 A6 =−2.10655E−06 A8 = 0.00000E+00 10th surface k = 0 A4 = 5.76382E−05 A6 =−8.00870E−07 A8 = 0.00000E+00 15th surface k = 0 A4 = −1.01844E−04 A6 =−3.50190E−07 A8 = 0.00000E+00 Zoom data When D0 (distance from object upto 1st surface) is ∞ wide-angle end intermediate telephoto end Focallength 6.079 13.784 18.095 FNO. 2.85 3.41 3.73 D7 12.58 4.57 0.8 D101.59 9.6 13.37 D11 1.42 5.65 10.43 D14 8.13 7.54 2.99 D17 5.12 1.48 1.25D21 1.33 1.2 1.09

THIRTEENTH EMBODIMENT

FIG. 25 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a thirteenth embodimentof the present invention.

FIG. 26A, FIG. 26B, and FIG. 26C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the thirteenth embodiment, where,FIG. 26A shows the state at the wide angle end, FIG. 26B shows theintermediate state, and FIG. 26C shows the state at the telephoto end.

The zoom lens of the thirteenth embodiment, as shown in FIG. 25, has afirst lens group G1, a second lens group G2, an aperture stop S, a thirdlens group G3, and a fourth lens group G4 in this order from the objectside. In the diagram, LPF is a low-pass filter, CG is a cover glass, andI is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having aconvex surface directed toward the object side, a prism L212, and acemented lens which is formed by a biconvex lens L213 and a biconcavelens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by abiconvex lens L221 and a negative meniscus lens L222 having a convexsurface directed toward an image side, and has a positive refractingpower as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconcave lens L231 and the positive meniscus lens L232 having a convexsurface directed toward the object side, and has a negative refractingpower as a whole.

The fourth lens group G4 includes a cemented lens which is formed by abiconvex lens L241 and a negative meniscus lens L242 having a concavesurface directed toward the object side, and has a positive refractingpower as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward theobject side, the aperture stop S is fixed, the third lens group G3 movestoward the image side, and the fourth lens group G4 moves toward theimage side.

An aspheric surface is provided on a surface toward the object of thebiconvex lens L213 in the first lens group, a surface on the object sideof the biconvex lens L221 and a surface on the image side of thenegative meniscus lens L222 having the convex surface directed towardthe image side in the second lens group G2, and a surface on the objectside of the biconvex lens in the fourth lens group G4.

Next, numerical data of the thirteenth embodiment will be enumerated.

Numerical data 13 r1 = 33.982 d1 = 1.1 Nd1 = 1.7432 νd1 = 49.34 r2 =10.473 d2 = 3 r3 = ∞ d3 = 12.5 Nd3 = 1.801 νd3 = 34.97 r4 = ∞ d4 = 0.4r5 = 420.903 d5 = 2.2 Nd5 = 1.8061 νd5 = 40.92 (Aspheric surface) r6 =−12.739 d6 = 0.7 Nd6 = 1.51823 νd6 = 58.9 r7 = 18.9 d7 = D7 r8 = 11.769d8 = 4 Nd8 = 1.497 νd8 = 81.54 (Aspheric surface) r9 = −21.158 d9 = 0.35Nd9 = 1.54856 νd9 = 7.04 r10 = −25.172 d10 = D10 (Aspheric surface) r11= Aperture stop d11 = D11 r12 = −12.515 d12 = 0.7 Nd12 = 1.48749 νd12 =70.23 r13 = 10.408 d13 = 1.6 Nd13 = 1.83481 νd13 = 42.71 r14 = 24.37 d14= D14 r15 = 13.942 d15 = 3.5 Nd15 = 1.7432 νd15 = 49.34 (Asphericsurface) r16 = −6 d16 = 0.7 Nd16 = 1.84666 νd16 = 23.78 r17 = −14.625d17 = D17 r18 = ∞ d18 = 1.44 Nd18 = 1.54771 νd18 = 62.84 r19 = ∞ d19 =0.8 r20 = ∞ d20 = 0.6 Nd20 = 1.51633 νd20 = 64.14 r21 = ∞ d21 = D21Aspherical coefficients  5th surface k = 0 A4 = 1.74566E−05 A6 =6.67000E−08 A8 = 0.00000E+00  8th surface k = 0 A4 = −1.19200E−04 A6 =−2.02183E−07 A8 = −4.21441E−07 10th surface k = 0 A4 = −2.32245E−05 A6 =3.20470E−07 A8 = −1.28129E−06 15th surface k = 0 A4 = −1.55574E−04 A6 =−1.65793E−07 A8 = 5.27383E−08 Zoom data When D0 (distance from object upto 1st surface) is ∞ wide-angle end intermediate telephoto end Focallength 6.013 13.699 17.991 FNO. 2.89 3.48 3.83 D7 13.94 4 0.8 D10 1.611.55 14.74 D11 1.4 6.02 9.19 D14 6.37 4.95 3 D17 5.62 2.41 1.2 D21 1.361.36 1.36

FOURTEENTH EMBODIMENT

FIG. 27 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a fourteenth embodimentof the present invention.

FIG. 28A, FIG. 28B, and FIG. 28C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the fourteenth embodiment of thepresent invention, where, FIG. 28A shows the state at the wide angleend, FIG. 28B shows the intermediate state, and FIG. 28C shows the stateat the telephoto end.

The zoom lens of the fourteenth embodiment, as shown in FIG. 27, has afirst lens group G1, a second lens group G2, an aperture stop S, a thirdlens group G3, and a fourth lens group G4 in this order from an objectside. In the diagram, LPF is a low-pass filter, CG is a cover glass, andI is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having aconvex surface directed toward the object side, a prism L212, and acemented lens which is formed by a positive meniscus lens L213 having aconvex surface directed toward an image side and a biconcave lens L214,and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by abiconvex lens L221 and a negative meniscus lens L222 having a convexsurface directed toward the image side, and has a positive refractingpower as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconcave lens L231 and a positive meniscus lens L232 having a convexsurface directed toward the object side, and has a negative refractingpower as a whole.

The fourth lens group G4 includes a cemented lens which is formed by abiconvex lens L241 and a negative meniscus lens L242 having a concavesurface directed toward the object side, and has a positive refractingpower as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward theobject side, the aperture stop S is fixed, the third lens group G3 movestoward the image side, and the fourth lens group G4 moves toward theimage side.

An aspheric surface is provided on a surface toward the object, of thepositive meniscus lens L213 having the convex surface directed towardthe image side in the first lens group G1, a surface on the object sideof the biconvex lens L221 and a surface on the image side of thenegative meniscus lens L222 having the convex surface directed towardthe image side in the second lens group G2, and a surface on the objectside, of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the fourteenth embodiment will be enumerated.

Numerical data 14 r1 = 21.697 d1 = 1.1 Nd1 = 1.7432 νd1 = 49.34 r2 =8.621 d2 = 3 r3 = ∞ d3 = 12.5 Nd3 = 1.94891 νd3 = 23.05 r4 = ∞ d4 = 0.4r5 = −61.481 d5 = 2.2 Nd5 = 1.82367 νd5 = 32.14 (Aspheric surface) r6 =−12.879 d6 = 0.7 Nd6 = 1.55419 νd6 = 58.44 r7 = 30.673 d7 = D7 r8 =15.245 d8 = 4 Nd8 = 1.50278 νd8 = 78.82 (Aspheric surface) r9 = −12 d9 =0.35 Nd9 = 1.65228 νd9 = 12.75 r10 = −14.968 d10 = D10 (Asphericsurface) r11 = Aperture stop d11 = D11 r12 = −19.694 d12 = 0.7 Nd12 =1.55228 νd12 = 49.08 r13 = 7.159 d13 = 1.6 Nd13 = 1.85942 νd13 = 42.23r14 = 24.86 d14 = D14 r15 = 15.192 d15 = 3.5 Nd15 = 1.7501 νd15 = 51.93(Aspheric surface) r16 = −6 d16 = 0.7 Nd16 = 1.80849 νd16 = 35.3 r17 =−39.907 d17 = D17 r18 = ∞ d18 = 1.44 Nd18 = 1.54771 νd18 = 62.84 r19 = ∞d19 = 0.8 r20 = ∞ d20 = 0.6 Nd20 = 1.51633 νd20 = 64.14 r21 = ∞ d21 =D21 Aspherical coefficients  5th surface k = 0 A4 = 4.46958E−05 A6 =4.51820E−07 A8 = 0  8th surface k = 0 A4 = −1.07884E−04 A6 =−2.45135E−06 A8 = 0.00000E+00 10th surface k = 0 A4 = 2.92065E−06 A6 =−1.30323E−06 A8 = 0.00000E+00 15th surface k = 0 A4 = −1.69708E−04 A6 =4.01584E−07 A8 = 0.00000E+00 Zoom data When D0 (distance from object upto 1st surface) is ∞ wide-angle end intermediate telephoto end Focallength 6.1 13.42 17.995 FNO. 3.45 3.91 4.55 D7 18.29 3.07 0.58 D10 2.8811.62 14.96 D11 0.85 5.17 12 D14 7.15 5.14 2.53 D17 4.47 4.43 2.92 D211.36 1.36 1.36

FIFTEENTH EMBODIMENT

FIG. 29 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a fifteenth embodiment ofthe present invention.

FIG. 30A, FIG. 30B, and FIG. 30C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the fifteenth embodiment, where,FIG. 30A shows the state at the wide angle end, FIG. 30B shows theintermediate state, and FIG. 30C shows the state at the telephoto end.

The zoom lens of the fifteenth embodiment, as shown in FIG. 29, has afirst lens group G1, a second lens group G2, an aperture stop S, a thirdlens group G3, and a fourth lens group G4 in this order from an objectside. In the diagram, LPF is a low-pass filter, CG is a cover glass, andI is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 havingthe convex surface directed toward the object side, the prism L212, anda cemented lens which is formed by a biconvex lens L213 and a biconcavelens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by abiconvex lens L221 and a negative meniscus lens L222 having a convexsurface directed toward an image side, and has a positive refractingpower as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconcave lens L231 and a positive meniscus lens L232 having a convexsurface directed toward the object side, and has a negative refractingpower as a whole.

The fourth lens group G4 includes a cemented lens which is formed by abiconvex lens L241 and a negative meniscus lens L242 having a concavesurface directed toward the object side, and has a positive refractingpower as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward theobject side, the aperture stop S is fixed, the third lens group G3 movestoward the image side, and the fourth lens group G4 moves toward theimage side.

An aspheric surface is provided on a surface on the object side, of thebiconvex lens L213 in the first lens group G1, a surface on the objectside of the biconvex lens L221 and a surface on the image side of thenegative meniscus lens L222 having the convex surface directed towardthe image side in the second lens group G2, and a surface on the objectside, of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the fifteenth embodiment will be enumerated.

Numerical data 15 r1 = 39.511 d1 = 1.1 Nd1 = 1.7432 νd1 = 49.34 r2 =9.954 d2 = 3 r3 = ∞ d3 = 12.5 Nd3 = 1.801 νd3 = 34.97 r4 = ∞ d4 = 0.4 r5= 50.212 d5 = 2.14 Nd5 = 1.8061 νd5 = 40.92 (Aspheric surface) r6 =−12.508 d6 = 0.7 Nd6 = 1.52 νd6 = 57 r7 = 15.872 d7 = D7 r8 = 11.955 d8= 4.86 Nd8 = 1.497 νd8 = 81.54 (Aspheric surface) r9 = −29.183 d9 = 0.35Nd9 = 1.59885 νd9 = 6.52 r10 = −36.717 d10 = D10 (Aspheric surface) r11= Aperture stop d11 = D11 r12 = −13.687 d12 = 0.7 Nd12 = 1.48749 νd12 =70.23 r13 = 8.399 d13 = 1.6 Nd13 = 1.83481 νd13 = 40.7 r14 = 18.182 d14= D14 r15 = 12.005 d15 = 3.5 Nd15 = 1.7432 νd15 = 49.34 (Asphericsurface) r16 = −6 d16 = 0.7 Nd16 = 1.84666 νd16 = 23.78 r17 = −16.33 d17= D17 r18 = ∞ d18 = 1.44 Nd18 = 1.54771 νd18 = 62.84 r19 = ∞ d19 = 0.8r20 = ∞ d20 = 0.6 Nd20 = 1.51633 νd20 = 64.14 r21 = ∞ d21 = D21Aspherical coefficients  5th surface k = 0 A4 = 1.86622E−05 A6 =−1.24351E−08 A8 = 0  8th surface k = 0 A4 = −5.16885E−05 A6 =3.34589E−07 A8 = 0.00000E+00 10th surface k = 0 A4 = 2.45844E−05 A6 =6.28246E−07 A8 = 0.00000E+00 15th surface k = 0 A4 = −1.76798E−04 A6 =4.99749E−07 A8 = 0.00000E+00 Zoom data When D0 (distance from object upto 1st surface) is ∞ wide-angle end intermediate telephoto end Focallength 6 13.7 17.999 FNO. 2.85 3.49 3.73 D7 15.39 4.68 0.8 D10 1.6 12.3116.2 D11 1.4 7.01 9.12 D14 6.3 4.1 3 D17 5.63 2.21 1.21 D21 1.36 1.361.36

SIXTEENTH EMBODIMENT

FIG. 31 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a sixteenth embodiment ofthe present invention.

FIG. 32A, FIG. 32B, and FIG. 32C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the sixteenth embodiment of thepresent invention, where, FIG. 32A shows the state at the wide angleend, FIG. 32B shows the intermediate state, and FIG. 32C shows the stateat the telephoto end.

The zoom lens of the sixteenth embodiment, as shown in FIG. 31, has afirst lens group G1, a second lens group G2, an aperture stop S, a thirdlens group G3, and a fourth lens group G4 in this order from the objectside. In the diagram, LPF is a low-pass filter, CG is a cover glass, andI is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having aconvex surface directed toward the object side, the prism L212, and acemented lens which is formed by a biconvex lens L213 and a biconcavelens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by abiconvex lens L221 and a negative meniscus lens L222 having a convexsurface directed toward an image side, and has a positive refractingpower as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconcave lens L231 and a positive meniscus lens L232 having a convexsurface directed toward the object side, and has a negative refractingpower as a whole.

The fourth lens group G4 includes a cemented lens which is formed by abiconvex lens L241 and a negative meniscus lens L242 having a concavesurface directed toward the object side, and has a positive refractingpower as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward theobject side, the aperture stop S is fixed, the third lens group G3 movestoward the image side, and the fourth lens group G4 moves toward theimage side.

An aspheric surface is provided on a surface on the object side, of thebiconvex lens L213 in the first lens group G1, a surface on the objectside of the biconvex lens L221 and a surface on the image side of thenegative meniscus lens L222 having the convex surface directed towardthe image side in the second lens group G2, and a surface on the objectside, of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the sixteenth embodiment will be enumerated.

Numerical data 16 r1 = 38.962 d1 = 1.1 Nd1 = 1.7432 νd1 = 49.34 r2 =9.911 d2 = 3 r3 = ∞ d3 = 12.5 Nd3 = 1.801 νd3 = 34.97 r4 = ∞ d4 = 0.4 r5= 47.772 d5 = 2.11 Nd5 = 1.8061 νd5 = 40.92 (Aspheric surface) r6 =−12.757 d6 = 0.7 Nd6 = 1.52 νd6 = 57 r7 = 15.478 d7 = D7 r8 = 11.780 d8= 5.1 Nd8 = 1.497 νd8 = 81.54 (Aspheric surface) r9 = −23.99 d9 = 0.35Nd9 = 1.79525 νd9 = 9.95 r10 = −31.574 d10 = D10 (Aspheric surface) r11= Aperture stop d11 = D11 r12 = −13.748 d12 = 0.7 Nd12 = 1.48749 νd12 =70.23 r13 = 8.46 d13 = 1.6 Nd13 = 1.83481 νd13 = 40.7 r14 = 18.241 d14 =D14 r15 = 12.049 d15 = 3.5 Nd15 = 1.7432 νd15 = 49.34 (Aspheric surface)r16 = −6 d16 = 0.7 Nd16 = 1.84666 νd16 = 23.78 r17 = −16.277 d17 = D17r18 = ∞ d18 = 1.44 Nd18 = 1.54771 νd18 = 62.84 r19 = ∞ d19 = 0.8 r20 = ∞d20 = 0.6 Nd20 = 1.51633 νd20 = 64.14 r21 = ∞ d21 = D21 Asphericalcoefficients  5th surface k = 0 A4 = 2.09655E−05 A6 = 1.33197E−08 A8 = 0 8th surface k = 0 A4 = −5.05955E−05 A6 = 3.02697E−07 A8 = 0.00000E+0010th surface k = 0 A4 = 2.20076E−05 A6 = 4.81649E−07 A8 = 0.00000E+0015th surface k = 0 A4 = −1.74494E−04 A6 = 4.58302E−07 A8 = 0.00000E+00Zoom data When D0 (distance from object up to 1st surface) is ∞wide-angle end intermediate telephoto end Focal length 5.999 10.39917.999 FNO. 2.85 3.32 3.72 D7 15.36 8.57 0.8 D10 1.6 8.39 16.16 D11 1.45.88 9.07 D14 6.29 4.21 3 D17 5.58 3.18 1.21 D21 1.36 1.36 1.36

SEVENTEENTH EMBODIMENT

FIG. 33 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a seventeenth embodimentof the present invention.

FIG. 34A, FIG. 34B, and FIG. 34C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the seventeenth embodiment,where, FIG. 34A shows the state at the wide angle end, FIG. 34B showsthe intermediate state, and FIG. 34C shows the state at the telephotoend.

The zoom lens of the seventeenth embodiment, as shown in FIG. 33, has afirst lens group G1, a second lens group G2, an aperture stop S, a thirdlens group G3, and a fourth lens group G4 in this order from an objectside. In the diagram, LPF is a low-pass filter, CG is a cover glass, andI is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having aconvex surface directed toward the object side, a prism L212, and acemented lens which is formed by a biconvex lens L213 and a biconcavelens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by abiconvex lens L221 and a negative meniscus lens L222 having a convexsurface directed toward an image side, and has a positive refractingpower as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconcave lens L231 and a positive meniscus lens L232 having a convexsurface directed toward the object side, and has a positive refractingpower as a whole.

The fourth lens group G4 includes a cemented lens which is formed by abiconvex lens L241 and the negative meniscus lens L242 having a concavesurface directed toward the object side, and has a positive refractingpower as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward theobject side, the aperture stop S is fixed, the third lens group G3 movestoward the image side, and the fourth lens group G4 moves toward theimage side.

An aspheric surface is provided on a surface on the object side, of thebiconvex lens L213 in the first lens group G1, a surface on the objectside of the biconvex lens L221 and a surface on the image side of thenegative meniscus lens L222 having the convex surface directed towardthe image side in the second lens group G2, and a surface on the objectside, of the biconvex lens in the fourth lens group G4.

Next, numerical data of the seventeenth embodiment will be enumerated.

Numerical data 17 r1 = 39.372 d1 = 1.1 Nd1 = 1.7432 νd1 = 49.34 r2 =9.927 d2 = 3 r3 = ∞ d3 = 12.5 Nd3 = 1.801 νd3 = 34.97 r4 = ∞ d4 = 0.4 r5= 45.949 d5 = 2.12 Nd5 = 1.8061 νd5 = 40.92 (Aspheric surface) r6 =−12.875 d6 = 0.7 Nd6 = 1.52 νd6 = 57 r7 = 15.221 d7 = D7 r8 = 11.744 d8= 5.22 Nd8 = 1.497 νd8 = 81.54 (Aspheric surface) r9 = −20.824 d9 = 0.35Nd9 = 1.9712 νd9 = 12.88 r10 = −27.330 d10 = D10 (Aspheric surface) r11= Aperture stop d11 = D11 r12 = −13.73 d12 = 0.7 Nd12 = 1.48749 νd12 =70.23 r13 = 8.492 d13 = 1.6 Nd13 = 1.83481 νd13 = 40.7 r14 = 18.325 d14= D14 r15 = 12.076 d15 = 3.5 Nd15 = 1.7432 νd15 = 49.34 (Asphericsurface) r16 = −6 d16 = 0.7 Nd16 = 1.84666 νd16 = 23.78 r17 = −16.273d17 = D17 r18 = ∞ d18 = 1.44 Nd18 = 1.54771 νd18 = 62.84 r19 = ∞ d19 =0.8 r20 = ∞ d20 = 0.6 Nd20 = 1.51633 νd20 = 64.14 r21 = ∞ d21 = D21Aspherical coefficients  5th surface k = 0 A4 = 2.17207E−05 A6 =1.35440E−08 A8 = 0  8th surface k = 0 A4 = −5.21380E−05 A6 = 2.41157E−07A8 = 0.00000E+00 10th surface k = 0 A4 = 1.71590E−05 A6 = 3.51620E−07 A8= 0.00000E+00 15th surface k = 0 A4 = −1.73599E−04 A6 = 4.60077E−07 A8 =0.00000E+00 Zoom data When D0 (distance from object up to 1st surface)is ∞ wide-angle end intermediate telephoto end Focal length 5.999 10.39917.999 FNO. 2.85 3.32 3.73 D7 15.34 8.57 0.8 D10 1.6 8.37 16.14 D11 1.45.88 9.07 D14 6.29 4.22 3 D17 5.58 3.17 1.21 D21 1.36 1.36 1.36

EIGHTEENTH EMBODIMENT

FIG. 35 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to an eighteenth embodimentof the present invention.

FIG. 36A, FIG. 36B, and FIG. 36C are diagrams showing the sphericalaberration; the astigmatism, the distortion, and the chromaticaberration of magnification a the time of the infinite object pointfocusing of the zoom lens according to the eighteenth embodiment, where,FIG. 36A shows the state at the wide angle end, the FIG. 36B shows theintermediate state, and FIG. 36C shows the state at the telephoto end.

The zoom lens of the eighteenth embodiment, as shown in FIG. 35, has afirst lens group G1, a second lens group G2, an aperture stop S, a thirdlens group G3, and a fourth lens group G4, in this order from an objectside. In the diagram, LPF is a low-pass filter, CG is a cover glass, andI is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having aconvex surface directed toward the object side, a prism L212, and acemented lens which is formed by a biconvex lens L213 and a biconcavelens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by abiconvex lens L221 and a negative meniscus lens L222 having a convexsurface directed toward an image side, and has a positive refractingpower as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconcave lens L231 and a positive meniscus lens L232 having a convexsurface directed toward the object side, and has a negative refractingpower as a whole.

The fourth lens group G4 includes a cemented lens which is formed by abiconvex lens L241, and a negative meniscus lens L242 having a concavesurface directed toward the object side, and has a positive refractingpower as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward theobject side, the aperture stop S is fixed, the third lens group G3 movestoward the image side, and the fourth lens group G4 moves toward theimage side.

An aspheric surface is provided on a surface on the object side, of thebiconvex lens L214 in the first lens group G1, a surface on the objectside of the biconvex lens L221 and a surface on the image side of thenegative meniscus lens L222 having the convex surface directed towardthe image side in the second lens group G2, and a surface on the objectside, of the biconvex lens in the fourth lens group G4.

Next, numerical data of the eighteenth embodiment will be enumerated.

Numerical data 18 r1 = 39.906 d1 = 1.1 Nd1 = 1.7432 νd1 = 49.34 r2 =9.964 d2 = 3 r3 = ∞ d3 = 12.5 Nd3 = 1.801 νd3 = 34.97 r4 = ∞ d4 = 0.4 r5= 44.825 d5 = 2.13 Nd5 = 1.8061 νd5 = 40.92 (Aspheric surface) r6 =−12.948 d6 = 0.7 Nd6 = 1.52 νd6 = 57 r7 = 15.168 d7 = D7 r8 = 11.641 d8= 5.09 Nd8 = 1.497 νd8 = 81.54 (Aspheric surface) r9 = −29.171 d9 = 0.35Nd9 = 2.05122 νd9 = 6.28 r10 = −33.680 d10 = D10 (Aspheric surface) r11= Aperture stop d11 = D11 r12 = −13.644 d12 = 0.7 Nd12 = 1.48749 νd12 =70.23 r13 = 8.503 d13 = 1.6 Nd13 = 1.83481 νd13 = 40.7 r14 = 18.44 d14 =D14 r15 = 12.109 d15 = 3.5 Nd15 = 1.7432 νd15 = 49.34 (Aspheric surface)r16 = −6 d16 = 0.7 Nd16 = 1.84666 νd16 = 23.78 r17 = −16.133 d17 = D17r18 = ∞ d18 = 1.44 Nd18 = 1.54771 νd18 = 62.84 r19 = ∞ d19 = 0.8 r20 = ∞d20 = 0.6 Nd20 = 1.51633 νd20 = 64.14 r21 = ∞ d21 = D21 Asphericalcoefficients  5th surface k = 0 A4 = 2.13457E−05 A6 = 1.64989E−08 A8 = 0 8th surface k = 0 A4 = −4.96465E−05 A6 = 3.28544E−07 A8 = 0.00000E+0010th surface k = 0 A4 = 1.83684E−05 A6 = 4.02729E−07 A8 = 0.00000E+0015th surface k = 0 A4 = −1.75253E−04 A6 = 4.15528E−07 A8 = 0.00000E+00Zoom data When D0 (distance from object up to 1st surface) is ∞wide-angle end intermediate telephoto end Focal length 6 10.399 17.999FNO. 2.84 3.31 3.72 D7 15.34 8.56 0.8 D10 1.6 8.37 16.14 D11 1.4 5.899.04 D14 6.27 4.18 3 D17 5.57 3.17 1.21 D21 1.36 1.36 1.36

NINETEENTH EMBODIMENT

FIG. 37 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a nineteenth embodimentof the present invention.

FIG. 38A, FIG. 38B, and FIG. 38C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the nineteenth embodiment of thepresent invention, where, FIG. 38A shows the state at the wide angleend, FIG. 38B shows the intermediate state, and FIG. 38C shows the stateat the telephoto end.

The zoom lens of the nineteenth embodiment, as shown in FIG. 37, has afirst lens group G1, a second lens group G2, an aperture stop S, a thirdlens group G3, a fourth lens group G4, and a fifth lens group G5, inthis order from an object side. In the diagram, LPF is a low-passfilter, CG is a cover glass, and I is an image pickup surface of anelectronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having aconvex surface directed toward the object side, a prism L212, and acemented lens which is formed by a negative meniscus lens L113 having aconvex surface directed toward the object side and a biconvex lens 114,and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121 and a positivemeniscus lens L122 having a convex surface directed toward the objectside, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconvex lens L131 and a biconcave lens L132, and has a positiverefracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having aconvex surface directed toward the object side, and has a negativerefracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has apositive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward animage side, the aperture stop S is fixed, the third lens group G3 movestoward the object side, the fourth lens group moves once to the imageside and then moves toward the object side, and the fifth lens group G5moves toward the image side.

An aspheric surface is provided on a surface on the object side of thenegative meniscus lens L113 having the convex surface directed towardthe object side in the first lens group G1, both surfaces of thebiconcave lens L121 in the second lens group G2, a surface on the objectside of the biconvex lens L131, and a surface on the image side, of thebiconcave lens L132 in the third lens group G3, and a surface on theobject side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the nineteenth embodiment will be enumerated.

Numerical data 19 r1 = 27.528 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 10.01d2 = 2.9 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 =19.259 d5 = 0.1 Nd5 = 1.60687 νd5 = 27.03 (Aspheric surface) r6 = 16.049d6 = 3.54 Nd6 = 1.741 νd6 = 52.64 r7 = −43.585 d7 = D7 r8 = −74.609 d8 =0.8 Nd8 = 1.8061 νd8 = 40.92 (Aspheric surface) r9 = 5.443 d9 = 0.7(Aspheric surface) r10 = 7.458 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11= 91.204 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 8.403 d13 = 6.46Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −10.035 d14 = 1 Nd14= 1.84666 νd14 = 23.78 r15 = 47.150 d15 = D15 (Aspheric surface) r16 =24.758 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 9.504 d17 = D17 r18 =10.540 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 =−222.308 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 =D23 Aspherical coefficients  5th surface k = 0 A4 = 7.49511E−06 A6 =6.72180E−08 A8 = 0.00000E+00  8th surface k = 0 A4 = 2.74050E−04 A6 =−1.05373E−05 A8 = 1.91437E−07 9th surface k = 0 A4 = −1.49959E−04 A6 =−1.84286E−05 A8 = −4.07805E−07 13th surface k = 0 A4 = 6.78959E−05 A6 =2.28068E−06 A8 = −1.02002E−08 15th surface k = 0 A4 = 4.73455E−04 A6 =1.84961E−05 A8 = −3.16845E−08 18th surface k = 0 A4 = −1.04278E−04 A6 =9.79328E−06 A8 = −2.57765E−07 Zoom data When D0 (distance from object upto 1st surface) is ∞ wide-angle end intermediate telephoto end Focallength 6.002 13.7 17.996 FNO. 2.86 4.73 5.67 D7 0.8 6.8 8.42 D11 9.023.01 1.39 D12 10.8 3.53 1.19 D15 1.2 11.73 13.72 D17 1.4 1.59 2.83 D194.84 1.4 0.51 D23 1.36 1.36 1.36

TWENTIETH EMBODIMENT

FIG. 39 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a twentieth embodiment ofthe present invention.

FIG. 40A, FIG. 40B, and FIG. 40C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the twentieth embodiment, where,FIG. 40A shows the state at the wide angle end, FIG. 40B shows theintermediate state, and FIG. 40C shows the state at the telephoto end.

The zoom lens of the twentieth embodiment, as shown in FIG. 39, has afirst lens group G1, a second lens group G2, an aperture stop S, a thirdlens group G3, a fourth lens group G4, and a fifth lens group G5, inthis order from an object side. In the diagram, LPF is a low-passfilter, CG is a cover glass, and I is an image pickup surface of anelectronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having aconvex surface directed toward the object side, a prism L112, and acemented lens which is formed by a negative meniscus lens L113 having aconvex surface directed toward the object side and a biconvex lens L114,and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121 and a positivemeniscus lens L122 having a convex surface directed toward the objectside, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconvex lens L131 and a biconcave lens L132, and has a positiverefracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having aconvex surface directed toward the object side, and has a negativerefracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has apositive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward animage side, the aperture stop S is fixed, the third lens group G3 movestoward the object side, the fourth lens group G4 moves once toward theimage side, and then moves toward the object side, and the fifth lensgroup G5 moves toward the image side.

An aspheric surface is provided on a surface on the object side of thenegative meniscus lens L113 having the convex surface directed towardthe object side in the first lens group G1, both surfaces of thebiconcave lens L121 in the second lens group G2, a surface on the objectside of the biconvex lens L131, and a surface on the image side, of thebiconcave lens L132 in the third lens group G3, and a surface on theobject side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the twentieth embodiment will be enumerated.

Numerical data 20 r1 = 28.438 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 =10.004 d2 = 2.9 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3r5 = 20.895 d5 = 0.1 Nd5 = 1.60258 νd5 = 18.58 (Aspheric surface) r6 =17.413 d6 = 3.06 Nd6 = 1.741 νd6 = 52.64 r7 = −37.246 d7 = D7 r8 =−78.978 d8 = 0.73 Nd8 = 1.8061 νd8 = 40.92 (Aspheric surface) r9 = 5.188d9 = 0.64 (Aspheric surface) r10 = 7.149 d10 = 1.47 Nd10 = 1.7552 νd10 =27.51 r11 = 121.309 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 8.146d13 = 7.35 Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −8.498d14 = 1 Nd14 = 1.84666 νd14 = 23.78 r15 = 50.867 d15 = D15 (Asphericsurface) r16 = 38.968 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 9.515d17 = D17 r18 = 9.852 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Asphericsurface) r19 = −328.893 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20= 62.84 r21 = ∞ d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14r23 = ∞ d23 = D23 Aspherical coefficients  5th surface k = 0 A4 =1.23119E−05 A6 = 8.84042E−08 A8 = 0  8th surface k = 0 A4 = 8.85570E−05A6 = −5.07500E−07 A8 = −1.21145E−07  9th surface k = 0 A4 = −5.11299E−04A6 = 8.61810E−06 A8 = −1.99402E−06 13th surface k = 0 A4 = −4.74670E−06A6 = 4.46373E−06 A8 = −8.38829E−08 15th surface k = 0 A4 = 5.04643E−04A6 = 8.30882E−06 A8 = 6.17273E−07 18th surface k = 0 A4 = −8.08479E−05A6 = 1.99506E−06 A8 = −1.12576E−08 Zoom data When D0 (distance fromobject up to 1st surface) is ∞ wide-angle end intermediate telephoto endFocal length 6 13.7 17.999 FNO. 2.86 3.93 5.06 D7 0.8 10.24 10.6 D1111.2 1.76 1.4 D12 8.75 4.27 1.2 D15 1.2 7.9 10.53 D17 1.28 1.42 3.34 D194.33 1.98 0.5 D23 1.36 1.36 1.36

TWENTY FIRST EMBODIMENT

FIG. 41 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a twenty first embodimentof the present invention.

FIG. 42A, FIG. 42B, and FIG. 42C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the twenty first embodiment,where, FIG. 42A shows the state at the wide angle end, FIG. 42B showsthe intermediate state, and FIG. 42C shows the state at the telephotoend.

The zoom lens of the twenty first embodiment, as shown in FIG. 41, has afirst lens group G1, a second lens group G2, an aperture stop S, a thirdlens group G3, a fourth lens group G4, and a fifth lens group G5, inthis order from an object side. In the diagram, LPF is a low-passfilter, CG is a cover glass, and I is an image pickup surface of anelectronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having aconvex surface directed toward the object side, a prism L112, and acemented lens which is formed by a negative meniscus lens L113 having aconvex surface directed toward the object side and a biconvex lens L114,and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121 and a positivemeniscus lens L122 having a convex surface directed toward the objectside, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconvex lens L131 and a biconcave lens L132, and has a positiverefracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having aconvex surface directed toward the object side, and has a negativerefracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has apositive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward animage side, the aperture stop S is fixed, the third lens group G3 movestoward the object side, the fourth lens group G4 moves once toward theimage side, and then moves toward the object side, and the fifth lensgroup G5 moves toward the image side.

An aspheric surface is provided on a surface on the object side of thenegative meniscus lens L113 having the convex surface directed towardthe object side in the first lens group G1, both surfaces of thebiconcave lens L121 in the second lens group G2, a surface on the objectside of the biconvex lens L131, and a surface on the image side of thebiconcave lens L132 in the third lens group G3, and a surface on theobject side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the twenty first embodiment will be enumerated.

Numerical data 21 r1 = 27.426 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 =10.031 d2 = 2.9 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3r5 = 19.203 d5 = 0.1 Nd5 = 1.69556 νd5 = 25.02 (Aspheric surface) r6 =16.038 d6 = 3.54 Nd6 = 1.741 νd6 = 52.64 r7 = −43.264 d7 = D7 r8 =−75.475 d8 = 0.8 Nd8 = 1.8061 νd8 = 40.92 (Aspheric surface) r9 = 5.450d9 = 0.7 (Aspheric surface) r10 = 7.448 d10 = 2.2 Nd10 = 1.7552 νd10 =27.51 r11 = 92.147 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 8.392d13 = 6.46 Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −10.047d14 = 1 Nd14 = 1.84666 νd14 = 23.78 r15 = 47.431 d15 = D15 (Asphericsurface) r16 = 24.831 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 9.493d17 = D17 r18 = 10.557 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Asphericsurface) r19 = −230.141 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20= 62.84 r21 = ∞ d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14r23 = ∞ d23 = D23 Aspherical coefficients  5th surface k = 0 A4 =1.12705E−05 A6 = −8.08778E−08 A8 = 0  7th surface k = 0 A4 = 2.73216E−04A6 = −1.02234E−05 A8 = 1.64643E−07 k = 0  9th surface k = 0 A4 =−1.46628E−04 A6 = −1.85741E−05 A8 = −4.55787E−07 13th surface k = 0 A4 =6.74961E−05 A6 = 2.14113E−06 A8 = −1.38046E−08 15th surface A4 =4.72765E−04 A6 = 1.81729E−05 A8 = −5.79597E−08 18th surface k = 0 A4 =−1.04231E−04 A6 = 9.85834E−06 A8 = −2.64507E−07 Zoom data When D0(distance from object up to 1st surface) is ∞ wide-angle endintermediate telephoto end Focal length 6.005 13.639 17.893 FNO. 2.864.73 5.67 D7 0.8 6.8 8.42 D11 9.02 3.01 1.39 D12 10.8 3.53 1.19 D15 1.211.73 13.72 D17 1.4 1.59 2.83 D19 4.84 1.4 0.51 D23 1.35 1.36 1.4

TWENTY SECOND EMBODIMENT

FIG. 43 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a twenty secondembodiment of the present invention.

FIG. 44A, FIG. 44B, and FIG. 44C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite objectpoint-focusing of the zoom lens according to the twenty secondembodiment, where, FIG. 44A shows the state at the wide angle end, FIG.44B shows the intermediate state, and FIG. 44C shows the state at thetelephoto end.

The zoom lens of the twenty second embodiment, as shown in FIG. 43, hasa first lens group G1, a second lens group G2, an aperture stop S, athird lens group G3, a fourth lens group G4, and a fifth lens group G5,in this order from an object side. In the diagram, LPF is a low-passfilter, CG is a cover glass, and I is an image pickup surface of anelectronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having aconvex surface directed toward the object side, a prism L112, and acemented lens which is formed by a negative meniscus lens L113 having aconvex surface directed toward the object side and a biconvex lens L114,and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121 and a positivemeniscus lens L122 having a convex surface directed toward the objectside, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconvex lens L131 and a biconcave lens L132, and has a positiverefracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having aconvex surface directed toward the object side, and has a negativerefracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has apositive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward animage side, the aperture stop S is fixed, the third lens group G3 movestoward the object side, the fourth lens group G4 moves once toward theimage side, and then moves toward the object side, and the fifth lensgroup G5 moves toward the image side.

An aspheric surface is provided on a surface on the object side of thenegative meniscus lens L113 having the convex surface directed towardthe object side in the first lens group G1, both surfaces of thebiconcave lens L121 in the second lens group G2, a surface on the objectside of the biconvex lens L131, and a surface on the image side of thebiconcave lens L132 in the third lens group G3, and a surface on theobject side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the twenty second embodiment will be enumerated.

Numerical data 22 r1 = 28.32 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 10.005d2 = 2.9 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 =20.841 d5 = 0.1 Nd5 = 1.72568 νd5 = 18.68 (Aspheric surface) r6 = 17.368d6 = 2.82 Nd6 = 1.741 νd6 = 52.64 r7 = −35.523 d7 = D7 r8 = −77.234 d8 =0.61 Nd8 = 1.8061 νd8 = 40.92 (Aspheric surface) r9 = 5.150 d9 = 0.64(Aspheric surface) r10 = 7.099 d10 = 1.79 Nd10 = 1.7552 νd10 = 27.51 r11= 125.495 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 8.137 d13 = 7.8Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −8.325 d14 = 1 Nd14= 1.84666 νd14 = 23.78 r15 = 50.362 d15 = D15 (Aspheric surface) r16 =40.192 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 9.772 d17 = D17 r18 =9.992 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 =−337.631 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 =D23 Aspherical coefficients  5th surface k = 0 A4 = 1.00332E−05 A6 =7.42109E−08 A8 = 0  8th surface k = 0 A4 = 1.02571E−04 A6 = −5.01039E−06A8 = −2.49531E−09  9th surface k = 0 A4 = −4.89182E−04 A6 = −1.89829E−07A8 = −1.78387E−06 13th surface k = 0 A4 = −2.76088E−06 A6 = 2.53907E−06A8 = −5.24977E−08 15th surface k = 0 A4 = 5.14295E−04 A6 = 1.03006E−05A8 = 4.35904E−07 18th surface k = 0 A4 = −8.37722E−05 A6 = 3.59740E−06A8 = −5.85328E−08 Zoom data When D0 (distance from object up to 1stsurface) is ∞ wide-angle end intermediate telephoto end Focal length6.005 13.7 17.999 FNO. 2.86 3.83 4.95 D7 0.8 10.69 10.96 D11 11.56 1.681.4 D12 8.42 4.29 1.2 D15 1.2 7.13 9.86 D17 1.31 1.55 3.48 D19 4.11 2.050.5 D23 1.36 1.36 1.36

TWENTY THIRD EMBODIMENT

FIG. 45 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a twenty third embodimentof the present invention.

FIG. 46A, FIG. 46B, and FIG. 46C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the twenty third embodiment,where, FIG. 46A shows the state at the wide angle end, FIG. 46B showsthe intermediate state, and FIG. 46C shows the state at the telephotoend.

The zoom lens of the twenty third embodiment, as shown in FIG. 45, has afirst lens group G1, a second lens group G2, an aperture stop S, a thirdlens group G3, a fourth lens group G4, and a fifth lens group G5, inthis order from an object side. In the diagram, LPF is a low-passfilter, CG is a cover glass, and I is an image pickup surface of anelectronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having aconvex surface directed toward the object side, a prism L112, and acemented lens which is formed by a negative meniscus lens L113 having aconvex surface directed toward the object side, and a biconvex lensL114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121 and a positivemeniscus lens L122 having a convex surface directed toward the objectside, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconvex lens L131 and a biconcave lens L132, and has a positiverefracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having aconvex surface directed toward the object side, and has a negativerefracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has apositive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward animage side, the aperture stop S is fixed, the third lens group G3 movestoward the object side, the fourth lens group G4 moves once toward theimage side, and then moves toward the object side, and the fifth lensgroup G5 moves toward the image side.

An aspheric surface is provided on a surface on the object side of thenegative meniscus lens L113 having the convex surface directed towardthe object side in the first lens group G1, both surfaces of thebiconcave lens L121 in the second lens group G2, a surface on the objectside of the biconvex lens L131, and a surface on the image side of thebiconcave lens L132 in the third lens group G3, and a surface on theobject side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the twenty third embodiment will be enumerated.

Numerical data 23 r1 = 28.32 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 10.005d2 = 2.9 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 =20.841 d5 = 0.1 Nd5 = 1.72568 νd5 = 18.68 (Aspheric surface) r6 = 17.368d6 = 2.82 Nd6 = 1.741 νd6 = 52.64 r7 = −35.523 d7 = D7 r8 = −77.234 d8 =0.61 Nd8 = 1.8061 νd8 = 40.92 (Aspheric surface) r9 = 5.150 d9 = 0.64(Aspheric surface) r10 = 7.099 d10 = 1.79 Nd10 = 1.7552 νd10 = 27.51 r11= 125.495 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 8.137 d13 = 7.8Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −8.325 d14 = 1 Nd14= 1.84666 νd14 = 23.78 r15 = 50.362 d15 = D15 (Aspheric surface) r16 =40.192 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 9.772 d17 = D17 r18 =9.992 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 =−337.631 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 =D23 Aspherical coefficients  5th surface k = 0 A4 = 1.00332E−05 A6 =7.42109E−08 A8 = 0  8th surface k = 0 A4 = 1.02571E−04 A6 = −5.01039E−06A8 = −2.49531E−09  9th surface k = 0 A4 = −4.89182E−04 A6 = −1.89829E−07A8 = −1.78387E−06 13th surface k = 0 A4 = −2.76088E−06 A6 = 2.53907E−06A8 = −5.24977E−08 15th surface k = 0 A4 = 5.14295E−04 A6 = 1.03006E−05A8 = 4.35904E−07 18th surface k = 0 A4 = −8.37722E−05 A6 = 3.59740E−06A8 = −5.85328E−08 Zoom data When D0 (distance from object up to 1stsurface) is ∞ wide-angle end intermediate telephoto end Focal length6.005 13.7 17.999 FNO. 2.86 3.83 4.95 D7 0.8 10.69 10.96 D11 11.56 1.681.4 D12 8.42 4.29 1.2 D15 1.2 7.13 9.86 D17 1.31 1.55 3.48 D19 4.11 2.050.5 D23 1.36 1.36 1.36

TWENTY FOURTH EMBODIMENT

FIG. 47 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a twenty fourthembodiment of the present invention.

FIG. 48A, FIG. 48B, and FIG. 48C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the twenty fourth embodiment,where, FIG. 48A shows the state at the wide angle end, FIG. 48B showsthe intermediate state, and FIG. 48C shows the state at the telephotoend.

The zoom lens of the twenty fourth embodiment, as shown in FIG. 47, hasa first lens group G1, a second lens group G2, an aperture stop S, athird lens group G3, a fourth lens group G4, and a fifth lens group, G5in this order from an object side. In the diagram, LPF is a low-passfilter, CG is a cover glass, and I is an image pickup surface of anelectronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having aconvex surface directed toward the object side, a prism L112, and acemented lens which is formed by a negative meniscus lens L113 having aconvex surface directed toward the object side, and a biconvex lensL114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121 and a positivemeniscus lens L122 having a convex surface directed toward the objectside, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconvex lens L131 and a biconcave lens L132, and has a positiverefracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having aconvex surface directed toward the object side, and has a negativerefracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has apositive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward animage side, the aperture stop S is fixed, the third lens group G3 movestoward the image side, the fourth lens group G4 moves once toward theimage side, and then moves toward the object side, and the fifth lensgroup G5 moves toward the image side.

An aspheric surface is provided on a surface on the object side of thenegative meniscus lens L113 having the convex surface directed towardthe object side in the first lens group G1, both surfaces of thebiconcave lens L121 in the second lens group G2, a surface on the objectside of the biconvex lens L131, and a surface on the image side of thebiconcave lens L132 in the third lens group G3, and a surface on theobject side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the twenty fourth embodiment will be enumerated.

Numerical data 24 r1 = 26.268 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 9.767d2 = 2.9 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 =18.845 d5 = 0.1 Nd5 = 1.65228 νd5 = 12.75 (Aspheric surface) r6 = 17.425d6 = 3.54 Nd6 = 1.741 νd6 = 52.64 r7 = −46.982 d7 = D7 r8 = −47.767 d8 =0.8 Nd8 = 1.8061 νd8 = 40.92 (Aspheric surface) r9 = 5.610 d9 = 0.7(Aspheric surface) r10 = 7.861 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11= 651.723 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 8.372 d13 = 6.59Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −10.413 d14 = 1 Nd14= 1.84666 νd14 = 23.78 r15 = 47.183 d15 = D15 (Aspheric surface) r16 =19.829 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 9.344 d17 = D17 r18 =11.290 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 =−3235.664 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 =∞ d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 =D23 Aspherical coefficients  5th surface k = 0 A4 = 1.29265E−05 A6 =2.25482E−08 A8 = 0  8th surface k = 0 A4 = 3.13232E−04 A6 = −1.10497E−05A8 = 2.00754E−07  9th surface k = 0 A4 = −1.49920E−04 A6 = −1.69745E−05A8 = −3.47629E−07 13th surface k = 0 A4 = 6.03004E−05 A6 = 1.94139E−06A8 = 1.57565E−08 15th surface k = 0 A4 = 5.14589E−04 A6 = 9.41419E−06 A8= 4.95331E−07 18th surface k = 0 A4 = −8.99715E−05 A6 = 8.05337E−06 A8 =−1.55937E−07 Zoom data When D0 (distance from object up to 1st surface)is ∞ wide-angle end intermediate telephoto end Focal length 6.1 13.4217.995 FNO. 3.15 4.79 5.87 D7 1.44 7.29 8.68 D11 12.19 3.52 1.54 D127.82 3.25 0.84 D15 1.21 11.41 13.88 D17 1.42 1.6 2.93 D19 4.82 1.38 0.4D23 1.36 1.36 1.36

TWENTY FIFTH EMBODIMENT

FIG. 49 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a twenty fifth embodimentof the present invention.

FIG. 50A, FIG. 50B, and FIG. 50C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the twenty fifth embodiment,where, FIG. 50A shows a state at the wide angle end, FIG. 50B shows theintermediate state, and FIG. 50C shows the state at the telephoto end.

The zoom lens of the twenty fifth embodiment, as shown in FIG. 49, has afirst lens group G1, a second lens group G2, an aperture stop S, a thirdlens group G3, a fourth lens group G4, and a fifth lens group G5, inthis order from an object side. In the diagram, LPF is a low-passfilter, CG is a cover glass, and I is an image pickup surface of anelectronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having aconvex surface directed toward the object side, a prism L112, and acemented lens which is formed by a negative meniscus lens L113 having aconvex surface directed toward the object side, and a biconvex lensL114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121 and a positivemeniscus lens L122 having a convex surface directed toward the objectside, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconvex lens L131 and a biconcave lens L132, and has a positiverefracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having aconvex surface directed toward the object side, and has a negativerefracting power as a whole.

The fifth lens group G5 includes a positive meniscus lens L142 having aconvex surface directed toward the object side, and has a positiverefracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward animage side, the aperture stop S is fixed, the third lens group G3 movestoward the object side, the fourth lens group G4 moves once toward theimage side, and then moves toward the object side, and the fifth lensgroup G5 moves toward the image side.

An aspheric surface is provided on a surface of the object side of thenegative meniscus lens L113 having the convex surface directed towardthe object side in the first lens group G1, both surfaces of thebiconcave lens L121 in the second lens group G2, a surface on the objectside of the biconvex lens L131, and a surface on the image side of thebiconcave lens L132 in the third lens group G3, and a surface on theobject side of the positive meniscus lens L142 having the convex surfacedirected toward the object side in the fifth lens group G5.

Next, numerical data of the twenty fifth embodiment will be enumerated.

Numerical data 25 r1 = 23.104 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 9.993d2 = 2.9 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 =144.417 d5 = 0.1 Nd5 = 1.59885 νd5 = 6.52 (Aspheric surface) r6 =120.347 d6 = 3.54 Nd6 = 1.741 νd6 = 52.64 r7 = −15.632 d7 = D7 r8 =−67.973 d8 = 0.8 Nd8 = 1.8061 νd8 = 40.92 (Aspheric surface) r9 = 5.079d9 = 0.7 (Aspheric surface) r10 = 7.029 d10 = 2.2 Nd10 = 1.7552 νd10 =27.51 r11 = 101.993 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 7.719d13 = 6.28 Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −9.571d14 = 1 Nd14 = 1.84666 νd14 = 23.78 r15 = 34.509 d15 = D15 (Asphericsurface) r16 = 39.476 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 9.117d17 = D17 r18 = 7.840 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Asphericsurface) r19 = 34.132 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 =62.84 r21 = ∞ d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14r23 = ∞ d23 = D23 Aspherical coefficients  5th surface k = 0 A4 =−4.37427E−05 A6 = 4.88599E−07 A8 = 0  8th surface k = 0 A4 =−4.24746E−04 A6 = 1.70408E−05 A8 = −5.77793E−07  9th surface k = 0 A4 =−1.15464E−03 A6 = 3.78562E−05 A8 = −3.07050E−06 13th surface k = 0 A4 =1.41938E−04 A6 = −5.92299E−07 A8 = 7.51323E−08 15th surface k = 0 A4 =9.41257E−04 A6 = −6.26116E−06 A8 = 1.51062E−06 18th surface k = 0 A4 =−7.24351E−05 A6 = −2.74136E−07 A8 = −7.56639E−08 Zoom data When D0(distance from object up to 1st surface) is ∞ wide-angle endintermediate telephoto end Focal length 6.005 13.7 17.999 FNO. 3.01 4.935.95 D7 0.8 6.91 8.38 D11 8.98 2.86 1.4 D12 10.51 3.71 1.2 D15 1.2 11.5613.88 D17 1.59 1.78 2.67 D19 4.97 1.21 0.5 D23 1.36 1.36 1.36

TWENTY SIXTH EMBODIMENT

FIG. 51 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a twenty sixth embodimentof the present invention.

FIG. 52A, FIG. 52B, and FIG. 52C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the twenty sixth embodiment,where, FIG. 52A shows the state at the wide angle end, FIG. 52B showsthe intermediate state, and FIG. 52C shows the state at the telephotoend.

The zoom lens of the twenty sixth embodiment, as shown in FIG. 51, has afirst lens group G1, a second lens group G2, an aperture stop S, a thirdlens group G3, a fourth lens group G4, and a fifth lens group G5 in thisorder from an object side. In the diagram, LPF is a low-pass filter, CGis a cover glass, and I is an image pickup surface of an electronicimage pickup element.

The first lens group G1 includes a negative meniscus lens L111 having aconvex surface directed toward the object side, a prism L112, and acemented lens which is formed by a negative meniscus lens L113 having aconvex surface directed toward the object side, and a biconvex lensL114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121 and a positivemeniscus lens L122 having a convex surface directed toward the objectside, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconvex lens L131 and a biconcave lens L132, and has a positiverefracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having aconvex surface directed toward the object side, and has a negativerefracting power as a whole.

The fifth lens group G5 includes a positive meniscus lens L142 having aconvex surface directed toward the object side, and has a positiverefracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward animage side, the aperture stop S is fixed, the third lens group G3 movestoward the object side, the fourth lens group G4 moves once toward theimage side, and then moves toward the object side, and the fifth lensgroup G5 moves toward the image side.

An aspheric surface is provided on a surface of the object side of thenegative meniscus lens L113 having the convex surface directed towardthe object side in the first lens group G1, both surfaces of thebiconcave lens L121 in the second lens group G2, a surface on the objectside of the biconvex lens L131, and a surface on the image side of thebiconcave lens L132 in the third lens group G3, and a surface on theobject side of the positive meniscus lens L142 having the convex surfacedirected toward the object side in the fifth lens group G5.

Next, numerical data of the twenty sixth embodiment will be enumerated.

Numerical data 26 r1 = 23.339 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 9.998d2 = 2.9 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 =100.200 d5 = 0.1 Nd5 = 1.79525 νd5 = 9.95 (Aspheric surface) r6 = 83.501d6 = 3.54 Nd6 = 1.741 νd6 = 52.64 r7 = −16.063 d7 = D7 r8 = −45.653 d8 =0.8 Nd8 = 1.8061 νd8 = 40.92 (Aspheric surface) r9 = 5.378 d9 = 0.7(Aspheric surface) r10 = 7.441 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11= 202.84 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 7.519 d13 = 6.32Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −10.334 d14 = 1 Nd14= 1.84666 νd14 = 23.78 r15 = 26.284 d15 = D15 (Aspheric surface) r16 =28.574 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 8.89 d17 = D17 r18 =7.764 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19 =32.431 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 =D23 Aspherical coefficients 5th surface k = 0 A4 = −2.65536E−05 A6 =3.17647E−07 A8 = 0 8th surface k = 0 A4 = −3.26054E−04 A6 = 1.26273E−05A8 = −4.63097E−07 9th surface k = 0 A4 = −9.57291E−04 A6 = 2.85872E−05A8 = −2.27299E−06 13th surface k = 0 A4 = 1.05906E−04 A6 = 3.76011E−07A8 = 3.75282E−08 15th surface k = 0 A4 = 9.47239E−04 A6 = −1.75798E−06A8 = 1.62992E−06 18th surface k = 0 A4 = −8.98935E−05 A6 = 9.26013E−07A8 = −9.48654E−08 Zoom data When D0 (distance from object up to 1stsurface) is ∞ wide-angle end intermediate telephoto end Focal length6.001 13.7 18 FNO. 3.01 4.93 5.92 D7 0.8 6.87 8.47 D11 9.07 3 1.4 D1210.55 3.61 1.2 D15 1.2 11.39 13.85 D17 1.66 1.82 2.52 D19 4.66 1.26 0.5D23 1.36 1.36 1.36

TWENTY SEVENTH EMBODIMENT

FIG. 53 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a twenty seventhembodiment of the present invention.

FIG. 54A, FIG. 54B, and FIG. 54C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the twenty seventh embodiment,where, FIG. 54A shows the state at the wide angle end, FIG. 54B showsthe intermediate state, and FIG. 54C shows the state at the telephotoend.

The zoom lens of the twenty seventh embodiment, as shown in FIG. 53, hasa first lens group G1, a second lens group G2, an aperture stop S, athird lens group G3, a fourth lens group G4, and a fifth lens group G5,in this order from the object side. In the diagram, LPF is a low-passfilter, CG is a cover glass, and I is an image pickup surface of anelectronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having aconvex surface directed toward the object side, a prism L112, and acemented lens which is formed by a negative meniscus lens L113 having aconvex surface directed toward the object side, and a biconvex lensL114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121 and a positivemeniscus lens L122 having a convex surface directed toward the objectside, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconvex lens L131 and a biconcave lens L132, and has a positiverefracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having aconvex surface directed toward the object side, and has a negativerefracting power as a whole.

The fifth lens group G5 includes a positive meniscus lens L142 having aconvex surface directed toward the object side, and has a positiverefracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward animage side, the aperture stop S is fixed, the third lens group G3 movestoward the object side, the fourth lens group G4 moves once toward theimage side, and then moves toward the object side, and the fifth lensgroup G5 moves toward the image side.

An aspheric surface is provided on a surface of the object side of thenegative meniscus lens L113 having the convex surface directed towardthe object side in the first lens group G1, both surfaces of thebiconcave lens L121 in the second lens group G2, a surface on the objectside of the biconvex lens L131, and a surface on the image side of thebiconcave lens L132 in the third lens group G3, and a surface on theobject side of the positive meniscus lens L142 having the convex surfacedirected toward the object side in the fifth lens group G5.

Next, numerical data of the twenty seventh embodiment will beenumerated.

Numerical data 27 r1 = 23.412 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 9.999d2 = 2.9 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 =71.727 d5 = 0.1 Nd5 = 1.9712 νd5 = 12.88 (Aspheric surface) r6 = 59.773d6 = 3.54 Nd6 = 1.741 νd6 = 52.64 r7 = −16.653 d7 = D7 r8 = −36.331 d8 =0.8 Nd8 = 1.8061 νd8 = 40.92 (Aspheric surface) r9 = 5.425 d9 = 0.7(Aspheric surface) r10 = 7.528 d10 = 2.2 Nd10 = 1.7552 νd10 = 27.51 r11= 1523.438 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 7.312 d13 =6.35 Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −10.511 d14 = 1Nd14 = 1.84666 νd14 = 23.78 r15 = 22.264 d15 = D15 (Aspheric surface)r16 = 31.087 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 9.171 d17 = D17r18 = 7.719 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Aspheric surface) r19= 34.976 d19 = D19 r20 = ∞ D20 = 1.9 Nd20 = 1.54771 νd20 = 62.84 r21 = ∞d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14 r23 = ∞ d23 =D23 Aspherical coefficients 5th surface k = 0 A4 = −1.63140E−05 A6 =2.12684E−07 A8 = 0 8th surface k = 0 A4 = −1.88552E−04 A6 = 7.75646E−06A8 = −3.54924E−07 9th surface k = 0 A4 = −8.03970E−04 A6 = 2.18772E−05A8 = −2.04118E−06 13th surface k = 0 A4 = 8.46048E−05 A6 = 8.81547E−07A8 = 1.40013E−08 15th surface k = 0 A4 = 9.97088E−04 A6 = 1.26510E−06 A8= 1.91272E−06 18th surface k = 0 A4 = −1.04269E−04 A6 = 9.09683E−07 A8 =−9.18645E−08 Zoom data When D0 (distance from object up to 1st surface)is ∞ wide-angle end intermediate telephoto end Focal length 6.001 13.718 FNO. 3.02 4.95 5.89 D7 0.8 6.83 8.53 D11 9.13 3.11 1.4 D12 10.31 3.471.2 D15 1.2 11.21 13.79 D17 1.84 1.82 2.3 D19 4.44 1.28 0.5 D23 1.361.36 1.36

TWENTY EIGHTH EMBODIMENT

FIG. 55 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a twenty eighthembodiment of the present invention.

FIG. 56A, FIG. 56B, and FIG. 56C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the twenty eighth embodiment,where, FIG. 56A shows the state at the wide angle end, FIG. 56B showsthe intermediate state, and FIG. 56C shows the state at the telephotoend.

The zoom lens of the twenty eighth embodiment, as shown in FIG. 55 has afirst lens group G1, a second lens group G2, an aperture stop S, a thirdlens group G3, a fourth lens group G4, and a fifth lens group G5 in thisorder from an object side. In the diagram, LPF is a low-pass filter, CGis a cover glass, and I is an image pickup surface of an electronicimage pickup element.

The first lens group G1 includes a negative meniscus lens L111 having aconvex surface directed toward the object side, a prism L112, and acemented lens which is formed by a negative meniscus lens L113 having aconvex surface directed toward the object side, and a biconvex lensL114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121 and a biconvexlens L122, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconvex lens L131 and a biconcave lens L132, and has a positiverefracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having aconvex surface directed toward the object side, and has a negativerefracting power as a whole.

The fifth lens group G5 includes a positive meniscus lens L142 having aconvex surface directed toward the object side, and has a positiverefracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward animage side, the aperture stop S is fixed, the third lens group G3 movestoward the object side, the fourth lens group G4 moves once toward theimage side, and then moves toward the object side, and the fifth lensgroup G5 moves toward the image side.

An aspheric surface is provided on a surface of the object side of thenegative meniscus lens L113 having the convex surface directed towardthe object side in the first lens group G1, both surfaces of thebiconcave lens L121 in the second lens group G2, a surface on the objectside of the biconvex lens L131, and a surface on the image side of thebiconcave lens L132 in the third lens group G3, and a surface on theobject side of the positive meniscus lens L142 having the convex surfacedirected toward the object side in the fifth lens group G5.

Next, numerical data of the twenty eighth embodiment will be enumerated.

Numerical data 28 r1 = 22.766 d1 = 1 Nd1 = 1.8061 νd1 = 40.92 r2 = 9.996d2 = 2.9 r3 = ∞ d3 = 12 Nd3 = 1.8061 νd3 = 40.92 r4 = ∞ d4 = 0.3 r5 =201.902 d5 = 0.1 Nd5 = 2.05122 νd5 = 6.28 (Aspheric surface) r6 =168.251 d6 = 3.54 Nd6 = 1.741 νd6 = 52.64 r7 = −15.092 d7 = D7 r8 =−33.130 d8 = 0.8 Nd8 = 1.8061 νd8 = 40.92 (Aspheric surface) r9 = 5.469d9 = 0.7 (Aspheric surface) r10 = 7.619 d10 = 2.2 Nd10 = 1.7552 νd10 =27.51 r11 = −366.416 d11 = D11 r12 = Aperture stop d12 = D12 r13 = 7.087d13 = 6.41 Nd13 = 1.6935 νd13 = 53.21 (Aspheric surface) r14 = −10.191d14 = 1 Nd14 = 1.84666 νd14 = 23.78 r15 = 19.545 d15 = D15 (Asphericsurface) r16 = 53.254 d16 = 0.6 Nd16 = 1.48749 νd16 = 70.23 r17 = 9.799d17 = D17 r18 = 7.635 d18 = 1.8 Nd18 = 1.7432 νd18 = 49.34 (Asphericsurface) r19 = 39.242 d19 = D19 r20 = ∞ d20 = 1.9 Nd20 = 1.54771 νd20 =62.84 r21 = ∞ d21 = 0.8 r22 = ∞ d22 = 0.75 Nd22 = 1.51633 νd22 = 64.14r23 = ∞ d23 = D23 Aspherical coefficients 5th surface k = 0 A4 =−2.29550E−05 A6 = 1.93244E−07 A8 = 0 8th surface k = 0 A4 = −2.64173E−04A6 = 1.12898E−05 A8 = −4.80203E−07 9th surface k = 0 A4 = −8.96070E−04A6 = 2.86426E−05 A8 = −2.27403E−06 13th surface k = 0 A4 = 8.06718E−05A6 = 3.66237E−07 A8 = 1.49391E−08 15th surface k = 0 A4 = 1.14232E−03 A6= −2.15240E−06 A8 = 2.64820E−06 18th surface k = 0 A4 = −1.11897E−04 A6= −1.49140E−07 A8 = −8.03112E−08 Zoom data When D0 (distance from objectup to 1st surface) is ∞ wide-angle end intermediate telephoto end Focallength 6.004 13.7 17.999 FNO. 3.05 5.03 5.99 D7 0.8 6.83 8.58 D11 9.183.14 1.4 D12 10.28 3.48 1.2 D15 1.2 11.15 13.77 D17 1.8 1.81 2.19 D194.37 1.22 0.5 D23 1.36 1.36 1.36

TWENTY NINTH EMBODIMENT

FIG. 57 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a twenty ninth embodimentof the present invention.

FIG. 58A, FIG. 58B, and FIG. 58C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the twenty ninth embodiment,where, FIG. 58A shows the state at the wide angle end, FIG. 58B showsthe intermediate state, and FIG. 58C shows the state at the telephotoend.

The zoom lens of the twenty ninth embodiment, as shown in FIG. 57, has afirst lens group G1, a second lens group G2, an aperture stop S, a thirdlens group G3, a fourth lens group G4, in this order from an objectside. In the diagram, LPF is a low-pass filter, CG is a cover glass, andI is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having aconvex surface directed toward the object side, a prism L212, and acemented lens which formed by a biconvex lens L213 and a biconcave lensL214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by abiconvex lens L221 and a negative meniscus lens L222 having a convexsurface directed toward an image side, and has a positive refractingpower as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconvex lens L231 and a positive meniscus lens L232 having a convexsurface directed toward the object side, and has a negative refractingpower as a whole.

The fourth lens group G4 includes a cemented lens which is formed by abiconvex lens L241 and a negative meniscus lens L242 having a concavesurface directed toward the object, and has a positive refracting poweras a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward theobject side, the aperture stop S is fixed, the third lens group movestoward the image side, and the fourth lens group G4 moves toward theimage side.

An aspheric surface is provided on a surface of the object side of thebiconvex lens L213 in the first lens group G1, a surface on the objectside of the biconvex lens L212 and a surface on the image side of thenegative meniscus lens L222 having the convex surface directed towardthe image side in the second lens group G2, and a surface on the objectside of the biconvex lens in the fourth lens group G4.

Next, numerical data of the twenty ninth embodiment will be enumerated.

Numerical data 29 r1 = 35.88 d1 = 1.1 Nd1 = 1.7432 νd1 = 49.34 r2 =10.46 d2 = 3 r3 = ∞ d3 = 12.5 Nd3 = 1.801 νd3 = 34.97 r4 = ∞ d4 = 0.4 r5= 41.274 d5 = 2.2 Nd5 = 1.8061 νd5 = 40.92 (Aspheric surface) r6 =−18.146 d6 = 0.7 Nd6 = 1.51823 νd6 = 58.9 r7 = 13.541 d7 = D7 r8 =10.842 d8 = 4 Nd8 = 1.497 νd8 = 81.54 (Aspheric surface) r9 = −12 d9 =0.35 Nd9 = 1.60687 νd9 = 27.03 r10 = −22.804 d10 = D10 (Asphericsurface) r11 = Aperture stop d11 = D11 r12 = −11.383 d12 = 0.7 Nd12 =1.48749 νd12 = 70.23 r13 = 9.58 d13 = 1.6 Nd13 = 1.83481 νd13 = 42.71r14 = 25.054 d14 = D14 r15 = 13.793 d15 = 3.5 Nd15 = 1.7432 νd15 = 49.34(Aspheric surface) r16 = −6 d16 = 0.7 Nd16 = 1.84666 νd16 = 23.78 r17 =−14.524 d17 = D17 r18 = ∞ d18 = 1.44 Nd18 = 1.54771 νd18 = 62.84 r19 = ∞d19 = 0.8 r20 = ∞ d20 = 0.6 Nd20 = 1.51633 νd20 = 64.14 r21 = ∞ d21 =D21 Aspherical coefficients 5th surface k = 0 A4 = 2.93525E−05 A6 =4.07936E−07 A8 = 0.00000E+00 8th surface k = 0 A4 = −6.76006E−05 A6 =−2.34849E−07 A8 = −4.21441E−07 10th surface k = 0 A4 = 2.25820E−05 A6 =5.99132E−07 A8 = −1.28129E−06 15th surface k = 0 A4 = −1.63254E−04 A6 =−9.51105E−07 A8 = 5.27383E−08 Zoom data When D0 (distance from object upto 1st surface) is ∞ wide-angle end intermediate telephoto end Focallength 6.011 13.702 17.986 FNO. 2.85 3.41 3.73 D7 13.83 4.09 0.8 D10 1.611.34 14.64 D11 1.4 5.76 8.78 D14 6.21 4.99 3 D17 5.32 2.18 1.15 D211.36 1.36 1.36

THIRTIETH EMBODIMENT

FIG. 59 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a thirtieth embodiment ofthe present invention.

FIG. 60A, FIG. 60B, and FIG. 60C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the thirtieth embodiment, where,FIG. 60A shows the state at the wide angle end, FIG. 60B shows theintermediate state, and FIG. 60C shows the state at the telephoto end.

The zoom lens of the thirtieth embodiment, as shown in FIG. 59, has afirst lens group G1, a second lens group G2, an aperture stop S, a thirdlens group G3, and a fourth lens group G4, in this order from an objectside. In the diagram, LPF is a low-pass filter, CG is a cover glass, andI is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having aconvex surface directed toward the object side, a prism L212, and acemented lens which is formed by a biconvex lens L213 and a biconcavelens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by abiconvex lens L221 and a negative meniscus lens L222 having a convexsurface directed toward an image side, and has a positive refractingpower as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconvex lens L231 and a positive meniscus lens L232 having a convexsurface directed toward the object side, and has a negative refractingpower as a whole.

The fourth lens group G4 includes a cemented lens which is formed by abiconvex lens L241 and a negative meniscus lens L242 having a concavesurface directed toward the object side, and has a positive refractingpower as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward theobject side, the aperture stop S is fixed, the third lens group movestoward the image side, and the fourth lens group moves toward the imageside.

An aspheric surface is provided on a surface of the object side of thebiconvex lens L213 in the first lens group G1, a surface on the objectside of the biconvex lens L221 and a surface on the image side of thenegative meniscus lens L222 having the convex surface directed towardthe image side in the second lens group G2, and a surface on the objectside of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the thirtieth embodiment will be enumerated.

Numerical data 30 r1 = 27.959 d1 = 1.1 Nd1 = 1.8061 νd1 = 40.92 r2 =10.419 d2 = 3 r3 = ∞ d3 = 12.5 Nd3 = 1.801 νd3 = 34.97 r4 = ∞ d4 = 0.4r5 = 2302.245 d5 = 2.2 Nd5 = 1.8061 νd5 = 40.92 (Aspheric surface) r6 =−13.25 d6 = 0.7 Nd6 = 1.51823 νd6 = 58.9 r7 = 19.658 d7 = D7 r8 = 13.858d8 = 4 Nd8 = 1.51633 νd8 = 64.14 (Aspheric surface) r9 = −12 d9 = 0.35Nd9 = 1.60689 νd9 = 18.58 r10 = −18.551 d10 = D10 (Aspheric surface) r11= Aperture stop d11 = D11 r12 = −12.567 d12 = 0.7 Nd12 = 1.48749 νd12 =70.23 r13 = 10.171 d13 = 1.6 Nd13 = 1.834 νd13 = 37.16 r14 = 23.736 d14= D14 r15 = 13.541 d15 = 3.5 Nd15 = 1.7432 νd15 = 49.34 (Asphericsurface) r16 = −6 d16 = 0.7 Nd16 = 1.84666 νd16 = 23.78 r17 = −15.389d17 = D17 r18 = ∞ d18 = 1.44 Nd18 = 1.54771 νd18 = 62.84 r19 = ∞ d19 =0.8 r20 = ∞ d20 = 0.6 Nd20 = 1.51633 νd20 = 64.14 r21 = ∞ d21 = D21Aspherical coefficients 5th surface k = 0 A4 = 1.94948E−05 A6 =1.62504E−07 A8 = 0 8th surface k = 0 A4 = 2.80468E−04 A6 = −7.76543E−06A8 = 0.00000E+00 10th surface k = 0 A4 = −6.44783E−06 A6 = −3.55641E−06A8 = 0.00000E+00 15th surface k = 0 A4 = −1.50887E−04 A6 = 5.00830E−07A8 = 0.00000E+00 Zoom data When D0 (distance from object up to 1stsurface) is ∞ wide-angle end intermediate telephoto end Focal length6.062 10.406 17.989 FNO. 2.85 3.29 3.9 D7 13.35 7.2 0.8 D10 1.58 7.7414.14 D11 1.39 5.06 10.1 D14 7.11 5.69 2.99 D17 5.77 3.52 1.19 D21 1.361.36 1.36

THIRTY FIRST EMBODIMENT

FIG. 61 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a thirty first embodimentof the present invention.

FIG. 62A, FIG. 62B, and FIG. 62C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the thirty first embodiment,where, FIG. 62A shows the state at the wide angle end, FIG. 62B showsthe intermediate state, and FIG. 62C shows the state at the telephotoend.

The zoom lens of the thirty first embodiment, as shown in FIG. 61, has afirst lens group G1, a second lens group G2, an aperture stop S, a thirdlens group G3, and a fourth lens group G4, in this order from an objectside. In the diagram LPF is a low-pass filter, CG is a cover glass, andI is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having aconvex surface directed toward the object side, a prism L212, and acemented lens which is formed by a biconvex lens L213 and a biconcavelens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by abiconvex lens L221 and a negative meniscus lens L222 having a convexsurface directed toward an image side, and has a positive refractingpower as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconcave lens L231 and a positive meniscus lens L232 having a convexsurface directed toward the object side, and has a positive refractingpower as a whole.

The fourth lens group G4 includes a cemented lens which is formed by abiconvex lens L241 and a negative meniscus lens L242 having a concavesurface directed toward the object side, and has a positive refractingpower as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward theobject side, the aperture stop S is fixed, the third lens group G3 movestoward the image side, and the fourth lens group G4 moves toward theimage side.

An aspheric surface is provided on a surface of the object side of thebiconvex lens L213 in the first lens group G1, a surface on the objectside, of the biconvex lens L221 and a surface on the image side, of thenegative meniscus lens L222 having the convex surface directed towardthe image side in the second lens group G2, and a surface on the objectside, of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the thirty first embodiment will be enumerated.

Numerical data 31 r1 = 34.959 d1 = 1.1 Nd1 = 1.7432 νd1 = 49.34 r2 =10.58 d2 = 3 r3 = ∞ d3 = 12.5 Nd3 = 1.801 νd3 = 34.97 r4 = ∞ d4 = 0.4 r5= 40.088 d5 = 2.2 Nd5 = 1.8061 νd5 = 40.92 (Aspheric surface) r6 =−17.816 d6 = 0.7 Nd6 = 1.51823 νd6 = 58.9 r7 = 13.677 d7 = D7 r8 =10.733 d8 = 4 Nd8 = 1.497 νd8 = 81.54 (Aspheric surface) r9 = −12 d9 =0.35 Nd9 = 1.69556 νd9 = 25.02 r10 = −22.311 d10 = D10 (Asphericsurface) r11 = Aperture stop d11 = D11 r12 = −11.366 d12 = 0.7 Nd12 =1.48749 νd12 = 70.23 r13 = 9.599 d13 = 1.6 Nd13 = 1.83481 νd13 = 42.71r14 = 24.942 d14 = D14 r15 = 13.911 d15 = 3.5 Nd15 = 1.7432 νd15 = 49.34(Aspheric surface) r16 = −6 d16 = 0.7 Nd16 = 1.84666 νd16 = 23.78 r17 =−14.707 d17 = D17 r18 = ∞ d18 = 1.44 Nd18 = 1.54771 νd18 = 62.84 r19 = ∞d19 = 0.8 r20 = ∞ d20 = 0.6 Nd20 = 1.51633 νd20 = 64.14 r21 = ∞ d21 =D21 Aspherical coefficients 5th surface k = 0 A4 = 3.14995E−05 A6 =2.53620E−07 A8 = 0 8th surface k = 0 A4 = −6.23568E−05 A6 = −2.89371E−07A8 = 0.00000E+00 10th surface k = 0 A4 = 1.93955E−05 A6 = 2.23840E−07 A8= 0.00000E+00 15th surface k = 0 A4 = −1.66755E−04 A6 = 4.47680E−07 A8 =0.00000E+00 Zoom data When D0 (distance from object up to 1st surface)is ∞ wide-angle end intermediate telephoto end Focal length 6.274 13.89818.212 FNO. 2.89 3.44 3.75 D7 13.83 4.09 0.8 D10 1.6 11.34 14.64 D11 1.45.76 8.78 D14 6.21 4.99 3 D17 5.32 2.18 1.15 D21 1.73 1.86 1.77

THIRTY SECOND EMBODIMENT

FIG. 63 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a thirty secondembodiment of the present invention.

FIG. 64A, FIG. 64B, and FIG. 64C are diagram showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the thirty second embodiment,where, FIG. 64A shows the state at the wide angle end, FIG. 64B showsthe intermediate state, and FIG. 64C shows the state at the telephotoend.

The zoom lens of the thirty second embodiment, as shown in FIG. 63, hasa first lens group G1, a second lens group G2, an aperture stop S, athird lens group G3, and a fourth lens group G4, in this order from anobject side. In this diagram, LPF is a low-pass filter, CG is a coverglass, and I is an image pickup surface of an electronic image pickupelement.

The first lens group G1 includes a negative meniscus lens L211 having aconvex surface directed toward the object side, a prism L212, and acemented lens which is formed by a positive meniscus lens L213 having aconvex surface directed toward an image side and a biconcave lens L214,and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by abiconvex lens L221 and a negative meniscus lens L222 having a convexsurface directed toward the image side, and has a positive refractingpower as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconcave lens L231 and a positive meniscus lens L232 having a convexsurface directed toward the object side, and has a negative refractingpower as a whole.

The fourth lens group G4 includes a cemented lens which is formed by abiconvex lens L241 and a negative meniscus lens L242 having a concavesurface directed toward the object side, and has a positive refractingpower as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward theobject side, the aperture stop S is fixed, the third lens group G3 movestoward the image side, and the fourth lens group G4 moves toward theimage side.

An aspheric surface is provided on a surface on the object side of thepositive meniscus lens L213 having the convex surface directed towardthe image side in the first lens group G1, a surface on the object sideof the biconvex lens L221 and a surface on the image side of thenegative meniscus lens L222 having a convex surface directed toward theimage side in the second lens group G2, and a surface on the object sideof the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the thirty second embodiment will be enumerated.

Numerical data 32 r1 = 25.752 d1 = 1.1 Nd1 = 1.804 νd1 = 46.57 r2 =11.454 d2 = 3 r3 = ∞ d3 = 12.5 Nd3 = 1.801 νd3 = 34.97 r4 = ∞ d4 = 0.4r5 = −50.569 d5 = 2.2 Nd5 = 1.8061 νd5 = 40.92 (Aspheric surface) r6 =−44.029 d6 = 0.7 Nd6 = 1.51823 νd6 = 58.9 r7 = 22.199 d7 = D7 r8 =10.827 d8 = 4 Nd8 = 1.51633 νd8 = 64.14 (Aspheric surface) r9 = −12 d9 =0.35 Nd9 = 1.72568 νd9 = 18.68 r10 = −13.508 d10 = D10 (Asphericsurface) r11 = Aperture stop d11 = D11 r12 = −34.096 d12 = 0.7 Nd12 =1.51823 νd12 = 58.9 r13 = 9.63 d13 = 1.6 Nd13 = 1.816 νd13 = 46.62 r14 =14.496 d14 = D14 r15 = 14.344 d15 = 3.5 Nd15 = 1.7432 νd15 = 49.34(Aspheric surface) r16 = −6 d16 = 0.7 Nd16 = 1.84666 νd16 = 23.78 r17 =−17.129 d17 = D17 r18 = ∞ d18 = 1.44 Nd18 = 1.54771 νd18 = 62.84 r19 = ∞d19 = 0.8 r20 = ∞ d20 = 0.6 Nd20 = 1.51633 νd20 = 64.14 r21 = ∞ d21 =D21 Aspherical coefficients  5th surface k = 0 A4 = 5.21908E−05 A6 =−4.28063E−08 A8 = 0  8th surface k = 0 A4 = 1.63431E−04 A6 =−1.97723E−06 A8 = 0.00000E+00 10th surface k = 0 A4 = 1.01894E−04 A6 =−8.53272E−07 A8 = 0.00000E+00 15th surface k = 0 A4 = −1.18081E−04 A6 =9.84689E−07 A8 = 0.00000E+00 Zoom data When D0 (distance from object upto 1st surface) is ∞ wide-angle end intermediate telephoto end Focallength 6.276 10.303 17.983 FNO. 2.85 2.9 3.56 D7 12.32 6.49 0.8 D10 1.637.34 13.14 D11 1.43 1.02 9.61 D14 8.72 10.15 2.97 D17 3.72 2.7 1.28 D211.36 1.36 1.36

THIRTY THIRD EMBODIMENT

FIG. 65 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a thirty third embodimentof the present invention.

FIG. 66A, FIG. 66B, and FIG. 66C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the thirty third embodiment,where, FIG. 66A shows the state at the wide angle end, FIG. 66B showsthe intermediate state, and FIG. 66C shows the state at the telephotoend.

The zoom lens of the thirty third embodiment, as shown in FIG. 65, has afirst lens group G1, a second lens group G2, an aperture stop S, a thirdlens group G3, and a fourth lens group G4, in this order from an objectside. In this diagram, LPF is a low-pass filter, CG is a cover glass,and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having aconvex surface directed toward the object side, a prism L212, and acemented lens which is formed by a positive meniscus lens L213 having aconvex surface directed toward an image side and a biconcave lens L214,and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by abiconvex lens L221 and a negative meniscus lens L222 having a convexsurface directed toward the image side, and has positive refractingpower as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconcave lens L231 and a positive meniscus lens L232 having a convexsurface directed toward the object side, and has a negative refractingpower as a whole.

The fourth lens group G4 includes a cemented lens which is formed by abiconvex lens L241 and a negative meniscus lens L242 having a concavesurface directed toward the object side, and has a positive refractingpower as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward theobject side, the aperture stop S is fixed, the third lens group G3 movestoward the image side, and the fourth lens group G4 moves toward theimage side.

An aspheric surface is provided on a surface on the object side of thepositive meniscus lens L213 having the convex surface directed towardthe image side in the first lens group G1, a surface on the object sideof the biconvex lens L221 and a surface on the image side of thenegative meniscus lens L222 having the convex surface directed towardthe image side in the second lens group G2, and a surface on the objectside of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the thirty third embodiment will be enumerated.

Numerical data 33 r1 = 25.752 d1 = 1.1 Nd1 = 1.804 νd1 = 46.57 r2 =11.454 d2 = 3 r3 = ∞ d3 = 12.5 Nd3 = 1.801 νd3 = 34.97 r4 = ∞ d4 = 0.4r5 = −50.569 d5 = 2.2 Nd5 = 1.8061 νd5 = 40.92 (Aspheric surface) r6 =−44.029 d6 = 0.7 Nd6 = 1.51823 νd6 = 58.9 r7 = 22.199 d7 = D7 r8 =10.827 d8 = 4 Nd8 = 1.51633 νd8 = 64.14 (Aspheric surface) r9 = −12 d9 =0.35 Nd9 = 1.72568 νd9 = 18.68 r10 = −13.508 d10 = D10 (Asphericsurface) r11 = Aperture stop d11 = D11 r12 = −34.096 d12 = 0.7 Nd12 =1.51823 νd12 = 58.9 r13 = 9.63 d13 = 1.6 Nd13 = 1.816 νd13 = 46.62 r14 =14.496 d14 = D14 r15 = 14.344 d15 = 3.5 Nd15 = 1.7432 νd15 = 49.34(Aspheric surface) r16 = −6 d16 = 0.7 Nd16 = 1.84666 νd16 = 23.78 r17 =−17.129 d17 = D17 r18 = ∞ d18 = 1.44 Nd18 = 1.54771 νd18 = 62.84 r19 = ∞d19 = 0.8 r20 = ∞ d20 = 0.6 Nd20 = 1.51633 νd20 = 64.14 r21 = ∞ d21 =D21 Aspherical coefficients  5th surface k = 0 A4 = 5.21908E−05 A6 =−4.28063E−08 A8 = 0  8th surface k = 0 A4 = 1.63431E−04 A6 =−1.97723E−06 A8 = 0.00000E+00 10th surface k = 0 A4 = 1.01894E−04 A6 =−8.53272E−07 A8 = 0.00000E+00 15th surface k = 0 A4 = −1.18081E−04 A6 =9.84689E−07 A8 = 0.00000E+00 Zoom data When D0 (distance from object upto 1st surface) is ∞ wide-angle end intermediate telephoto end Focallength 6.276 10.303 17.983 FNO. 2.85 2.9 3.56 D7 12.32 6.49 0.8 D10 1.637.34 13.14 D11 1.43 1.02 9.61 D14 8.72 10.15 2.97 D17 3.72 2.7 1.28 D211.36 1.36 1.36

THIRTY FOURTH EMBODIMENT

FIG. 67 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a thirty fourthembodiment of the present invention.

FIG. 68A, FIG. 68B, and FIG. 68C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the thirty fourth embodiment,where, FIG. 68A shows the state at the wide angle end, FIG. 68B showsthe intermediate state, and FIG. 68C shows the state at the telephotoend.

The zoom lens of the thirty fourth embodiment, as shown in FIG. 67, hasa first lens group G1, a second lens group G2, an aperture stop S, athird lens group G3, and a fourth lens group G4, in this order from anobject side. In this diagram, LPF is a low-pass filter, CG is a coverglass, and I is an image pickup surface of an electronic image pickupelement.

The first lens group G1 includes a negative meniscus lens L211 having aconvex surface directed toward the object side, a prism L212, and acemented lens which is formed by a positive meniscus lens L213 having aconvex surface directed toward an image side and a biconcave lens L214,and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by abiconvex lens L221 and a negative meniscus lens L222 having a convexsurface directed toward the image side, and has a positive refractingpower as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconcave lens L231 and a positive meniscus lens L232 having a convexsurface directed toward the object side, and has a negative refractingpower as a whole.

The fourth lens group G4 includes a cemented lens which is formed by abiconvex lens L241 and a negative meniscus lens L242 having a concavesurface directed toward the object side, and has a positive refractingpower as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward theobject side, the aperture stop S is fixed, the third lens group G3 movestoward the image side, and the fourth lens group G4 moves toward theimage side.

An aspheric surface is provided on a surface on the object side of thepositive meniscus lens L213 having the convex surface directed towardthe image side in the first lens group G1, a surface on the object sideof the biconvex lens L221 and a surface on the image side of thenegative meniscus lens L222 having the convex surface directed towardthe image side in the second lens group G2, and a surface on the objectside of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the thirty fourth embodiment will be enumerated.

Numerical data 34 r1 = 21.697 d1 = 1.1 Nd1 = 1.7432 vd1 = 49.34 r2 =8.621 d2 = 3 r3 = ∞ d3 = 12.5 Nd3 = 1.94891 vd3 = 23.05 r4 = ∞ d4 = 0.4r5 = −61.481 d5 = 2.2 Nd5 = 1.82367 vd5 = 32.14 (Aspheric surface) r6 =12.879 d6 = 0.7 Nd6 = 1.55419 vd6 = 58.44 r7 = 30.673 d17 = D7 r8 =15.245 d8 = 4 Nd8 = 1.50278 vd8 = 78.82 (Aspheric surface) r9 = −12 d9 =0.35 Nd9 = 1.65228 vd9 = 12.75 r10 = 14.968 d10 = D10 (Aspheric surface)r11 = Aperture stop d11 = D11 r12 = 19.694 d12 = 0.7 Nd12 = 1.55228 vd12= 49.08 r13 = 7.159 d13 = 1.6 Nd13 = 1.85942 vd13 = 42.23 r14 = 24.86d14 = D14 r15 = 15.192 d15 = 3.5 Nd15 = 1.7501 vd15 = 51.93 (Asphericsurface) r16 = −6 d16 = 0.7 Nd16 = 1.80849 vd16 = 35.3 r17 = −39.907 d17= D17 r18 = ∞ d18 = 1.44 Nd18 = 1.54771 vd18 = 62.84 r19 = ∞ d19 = 0.8r20 = ∞ d20 = 0.6 Nd20 = 1.51633 vd20 = 64.14 r21 = ∞ d21 = D21Aspherical coefficients 5th surface k = 0 A4 = 4.46958E-05 A6 =4.51820E-07 A8 = 0 8th surface k = 0 A4 = −1.07884E−04 A6 = −2.45135E−06A8 = 0.00000E+00 10th surface k = 0 A4 = 2.92065E−06 AG = 1.30323E−06 A8= 0.00000E+00 15th surface k = 0 A4 = −1.69708E−04 AG = 4.01584E−07 A8 =0.00000E+00 Zoom data When D0 (distance from object up to 1st surface)is ∞ wide-angle end intermediate telephoto end Focal length 6.1 13.4217.995 FNO. 3.45 3.91 4.55 D7 18.29 3.07 0.58 D10 2.88 11.62 14.96 D110.85 5.17 12 D14 7.15 5.14 2.53 D17 4.47 4.43 2.92 D21 1.36 1.36 1.36

THIRTY FIFTH EMBODIMENT

FIG. 69 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a thirty fifth embodimentof the present invention.

FIG. 70A, FIG. 70B, and FIG. 70C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the thirty fifth embodiment,where, FIG. 70A shows the state at the wide angle end, FIG. 70B showsthe intermediate state, and FIG. 70C shows the state at the telephotoend.

The zoom lens of the thirty fifth embodiment, as shown in FIG. 69, has afirst lens group G1, a second lens group G2, an aperture stop S, a thirdlens group G3, and a fourth lens group G4, in this order from an objectside. In this diagram, LPF is a low-pass filter, CG is a cover glass,and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having aconvex surface directed toward the object side, a prism L212, and acemented lens which is formed by a biconvex lens L213 and a biconcavelens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by abiconvex lens L221 and a negative meniscus lens L222 having a convexsurface directed toward an image side, and has a positive refractingpower as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconcave lens L231 and a positive meniscus lens L232 having a convexsurface directed toward the object side, and has a negative refractingpower as a whole.

The fourth lens group G4 includes a cemented lens which is formed by abiconvex lens L241 and a negative meniscus lens L242 having a concavesurface directed toward the object side, and has a positive refractingpower as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward theobject side, the aperture stop S is fixed, the third lens group G3 movestoward the image side, and the fourth lens group G4 moves toward theimage side.

An aspheric surface is provided on a surface on the object side of thebiconvex lens L213 in the first lens group G1, a surface on the objectside of the biconvex lens L221 and a surface on the image side of thenegative meniscus lens L222 having the convex surface directed towardthe image side in the second lens group G2, and a surface on the objectside of the biconvex lens in the fourth lens group G4.

Next, numerical data of the thirty fifth embodiment will be enumerated.

Numerical data 35 r1 = 39.511 d1 = 1.1 Nd1 = 1.7432 νd1 = 49.34 r2 =9.954 d2 = 3 r3 = ∞ d3 = 12.5 Nd3 = 1.801 νd3 = 34.97 r4 = ∞ d4 = 0.4 r5= 50.212 d5 = 2.14 Nd5 = 1.8061 νd5 = 40.92 (Aspheric surface) r6 =−12.508 d6 = 0.7 Nd6 = 1.52 νd6 = 57 r7 = 15.872 d7 = D7 r8 = 11.955 d8= 4.86 Nd8 = 1.497 νd8 = 81.54 (Aspheric surface) r9 = −29.183 d9 = 0.35Nd9 = 1.59885 νd9 = 6.52 r10 = −36.717 d10 = D10 (Aspheric surface) r11= Aperture stop d11 = D11 r12 = −13.687 d12 = 0.7 Nd12 = 1.48749 νd12 =70.23 r13 = 8.399 d13 = 1.6 Nd13 = 1.83481 νd13 = 40.7 r14 = 18.182 d14= D14 r15 = 12.005 d15 = 3.5 Nd15 = 1.7432 νd15 = 49.34 (Asphericsurface) r16 = −6 d16 = 0.7 Nd16 = 1.84666 νd16 = 23.78 r17 = −16.33 d17= D17 r18 = ∞ d18 = 1.44 Nd18 = 1.54771 νd18 = 62.84 r19 = ∞ d19 = 0.8r20 = ∞ d20 = 0.6 Nd20 = 1.51633 νd20 = 64.14 r21 = ∞ d21 = D21Aspherical coefficients  5th surface k = 0 A4 = 1.86622E−05 A6 =−1.24351E−08 A8 = 0  8th surface k = 0 A4 = −5.16885E−05 A6 =3.34589E−07 A8 = 0.00000E+00 10th surface k = 0 A4 = 2.45844E−05 A6 =6.28246E−07 A8 = 0.00000E+00 15th surface k = 0 A4 = −1.76798E−04 A6 =4.99749E−07 A8 = 0.00000E+00 Zoom data When D0 (distance from object upto 1st surface) is ∞ wide-angle end intermediate telephoto end Focallength 6 13.7 17.999 FNO. 2.85 3.49 3.73 D7 15.39 4.68 0.8 D10 1.6 12.3116.2 D11 1.4 7.01 9.12 D14 6.3 4.1 3 D17 5.63 2.21 1.21 D21 1.36 1.361.36

THIRTY SIXTH EMBODIMENT

FIG. 71 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a thirty sixth embodimentof the present invention.

FIG. 72A, FIG. 72B, and FIG. 72C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the thirty sixth embodiment,where, FIG. 72A shows the state at the wide angle end, FIG. 72B showsthe intermediate state, and FIG. 72C shows the state at the telephotoend.

The zoom lens of the thirty sixth embodiment, as shown in FIG. 71, has afirst lens group G1, a second lens group G2, an aperture stop S, a thirdlens group G3, and a fourth lens group G4, in this order from an objectside. In this diagram, LPF is a low-pass filter, CG is a cover glass,and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having aconvex surface directed toward the object side, a prism L212, and acemented lens which is formed by a biconvex lens L213 and a biconcavelens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by abiconvex lens L221 and a negative meniscus lens L222 having a convexsurface directed toward an image side, and has a positive refractingpower as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconcave lens L231 and a positive meniscus lens L232 having a convexsurface directed toward the object side, and has a negative refractingpower as a whole.

The fourth lens group G4 includes a cemented lens which is formed by abiconvex lens L241 and a negative meniscus lens L242 having a concavesurface directed toward the object side, and has a positive refractingpower as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward theobject side, the aperture stop S is fixed, the third lens group G3 movestoward the image side, and the fourth lens group G4 moves toward theimage side.

An aspheric surface is provided on a surface on the object side of thebiconvex lens L213 in the first lens group G1, a surface on the objectside of the biconvex lens L221 and a surface on the image side of thenegative meniscus lens L222 having the convex surface directed towardthe image side in the second lens group G2, and a surface on the objectside of the biconvex lens in the fourth lens group G4.

Next, numerical data of the thirty sixth embodiment will be enumerated.

Numerical data 36 r1 = 38.962 d1 = 1.1 Nd1 = 1.7432 νd1 = 49.34 r2 =9.911 d2 = 3 r3 = ∞ d3 = 12.5 Nd3 = 1.801 νd3 = 34.97 r4 = ∞ d4 = 0.4 r5= 47.772 d5 = 2.11 Nd5 = 1.8061 νd5 = 40.92 (Aspheric surface) r6 =−12.757 d6 = 0.7 Nd6 = 1.52 νd6 = 57 r7 = 15.478 d7 = D7 r8 = 11.780 d8= 5.1 Nd8 = 1.497 νd8 = 81.54 (Aspheric surface) r9 = −23.99 d9 = 0.35Nd9 = 1.79525 νd9 = 9.95 r10 = −31.574 d10 = D10 (Aspheric surface) r11= Aperture stop d11 = D11 r12 = −13.748 d12 = 0.7 Nd12 = 1.48749 νd12 =70.23 r13 = 8.46 d13 = 1.6 Nd13 = 1.83481 νd13 = 40.7 r14 = 18.241 d14 =D14 r15 = 12.049 d15 = 3.5 Nd15 = 1.7432 νd15 = 49.34 (Aspheric surface)r16 = −6 d16 = 0.7 Nd16 = 1.84666 νd16 = 23.78 r17 = −16.277 d17 = D17r18 = ∞ d18 = 1.44 Nd18 = 1.54771 νd18 = 62.84 r19 = ∞ d19 = 0.8 r20 = ∞d20 = 0.6 Nd20 = 1.51633 νd20 = 64.14 r21 = ∞ d21 = D21 Asphericalcoefficients  5th surface k = 0 A4 = 2.09655E−05 A6 = 1.33197E−08 A8 = 0 8th surface k = 0 A4 = −5.05955E−05 A6 = 3.02697E−07 A8 = 0.00000E+0010th surface k = 0 A4 = 2.20076E−05 A6 = 4.81649E−07 A8 = 0.00000E+0015th surface k = 0 A4 = −1.74494E−04 A6 = 4.58302E−07 A8 = 0.00000E+00Zoom data When D0 (distance from object up to 1st surface) is ∞wide-angle end intermediate telephoto end Focal length 5.999 10.39917.999 FNO. 2.85 3.32 3.72 D7 15.36 8.57 0.8 D10 1.6 8.39 16.16 D11 1.45.88 9.07 D14 6.29 4.21 3 D17 5.58 3.18 1.21 D21 1.36 1.36 1.36

THIRTY SEVENTH EMBODIMENT

FIG. 73 is a cross-sectional view along the optical axis showing anoptical arrangement at the wide angle end of a zoom lens according to athirty seventh embodiment of the present invention.

FIG. 74A, FIG. 74B, and FIG. 74C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the thirty seventh, where, FIG.74A shows the state at the wide angle end, FIG. 74B shows theintermediate state, and FIG. 74C shows the state at the telephoto end.

The zoom lens of the thirty seventh embodiment, as shown in FIG. 73, hasa first lens group G1, a second lens group G2, an aperture stop S, athird lens group G3, and the fourth lens group G4, in this order from anobject side. In this diagram, LPF is a low-pass filter, CG is a coverglass, and I is an image pickup surface of an electronic image pickupelement.

The first lens group G1 includes a negative meniscus lens L211 having aconvex surface directed toward the object side, a prism L212, and acemented lens which is formed by a biconvex lens L213 and a biconcavelens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by abiconvex lens L221 and a negative meniscus lens L222 having a convexsurface directed toward an image side, and has positive refracting poweras a whole.

The third lens group G3 includes a cemented lens which is formed by abiconcave lens L231 and a positive meniscus lens L232 having a convexsurface directed toward the object side, and has a negative refractingpower as a whole.

The fourth lens group G4 includes a cemented lens which is formed by abiconvex lens L241 and a negative meniscus lens L242 having a concavesurface directed toward the object side, and has a positive refractingpower as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward theobject side, the aperture stop S is fixed, the third lens group G3 movestoward the image side, and the fourth lens group G4 moves toward theimage side.

An aspheric surface is provided on a surface on the object side of thebiconvex lens L213 in the first lens group G1, a surface on the objectside of the biconvex lens L221 and a surface on the image side of thenegative meniscus lens L222 having the convex surface directed towardthe image side in the second lens group G2, and a surface on the objectside of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the thirty seventh embodiment will beenumerated.

Numerical data 37 r1 = 39.372 d1 = 1.1 Nd1 = 1.7432 νd1 = 49.34 r2 =9.927 d2 = 3 r3 = ∞ d3 = 12.5 Nd3 = 1.801 νd3 = 34.97 r4 = ∞ d4 = 0.4 r5= 45.949 d5 = 2.12 Nd5 = 1.8061 νd5 = 40.92 (Aspheric surface) r6 =−12.875 d6 = 0.7 Nd6 = 1.52 νd6 = 57 r7 = 15.221 d7 = D7 r8 = 11.744 d8= 5.22 Nd8 = 1.497 νd8 = 81.54 (Aspheric surface) r9 = −20.824 d9 = 0.35Nd9 = 1.9712 νd9 = 12.88 r10 = −27.330 d10 = D10 (Aspheric surface) r11= Aperture stop d11 = D11 r12 = −13.73 d12 = 0.7 Nd12 = 1.48749 νd12 =70.23 r13 = 8.492 d13 = 1.6 Nd13 = 1.83481 νd13 = 40.7 r14 = 18.325 d14= D14 r15 = 12.076 d15 = 3.5 Nd15 = 1.7432 νd15 = 49.34 (Asphericsurface) r16 = −6 d16 = 0.7 Nd16 = 1.84666 νd16 = 23.78 r17 = −16.273d17 = D17 r18 = ∞ d18 = 1.44 Nd18 = 1.54771 νd18 = 62.84 r19 = ∞ d19 =0.8 r20 = ∞ d20 = 0.6 Nd20 = 1.51633 νd20 = 64.14 r21 = ∞ d21 = D21Aspherical coefficients  5th surface k = 0 A4 = 2.17207E−05 A6 =1.35440E−08 A8 = 0  8th surface k = 0 A4 = −5.21380E−05 A6 = 2.41157E−07A8 = 0.00000E+00 10th surface k = 0 A4 = 1.71590E−05 A6 = 3.51620E−07 A8= 0.00000E+00 15th surface k = 0 A4 = −1.73599E−04 A6 = 4.60077E−07 A8 =0.00000E+00 Zoom data When D0 (distance from object up to 1st surface)is ∞ wide-angle end intermediate telephoto end Focal length 5.999 10.39917.999 FNO. 2.85 3.32 3.73 D7 15.34 8.57 0.8 D10 1.6 8.37 16.14 D11 1.45.88 9.07 D14 6.29 4.22 3 D17 5.58 3.17 1.21 D21 1.36 1.36 1.36

THIRTY EIGHTH EMBODIMENT

FIG. 75 is a cross-sectional view along the optical axis showing anoptical arrangement at the time of the infinite object point focusing atthe wide angle end of a zoom lens according to a thirty eighthembodiment of the present invention.

FIG. 76A, FIG. 76B, and FIG. 76C are diagrams showing the sphericalaberration, the astigmatism, the distortion, and the chromaticaberration of magnification at the time of the infinite object pointfocusing of the zoom lens according to the thirty eighth embodiment,where, FIG. 76A shows the state at the wide angle end, FIG. 76B showsthe intermediate state, and FIG. 76C shows the state at the telephotoend.

The zoom lens of the thirty eighth embodiment, as shown in FIG. 75, hasa first lens group G1, a second lens group G2, an aperture stop S, athird lens group G3, and a fourth lens group G4, in this order from anobject side. In this diagram, LPF is a low-pass filter, CG is a coverglass, and I is an image pickup surface of an electronic image pickupelement.

The first lens group includes a negative meniscus lens L211 having aconvex surface directed toward the object side, a prism L212, and acemented lens which is formed by a biconvex lens L213 and a biconcavelens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by abiconvex lens L221 and a negative meniscus lens L222 having a convexsurface directed toward an image side, and has a positive refractingpower as a whole.

The third lens group G3 includes a cemented lens which is formed by abiconcave lens L231 and a positive meniscus lens L232 having a convexsurface directed toward the object side, and has a positive refractingpower as a whole.

The fourth lens group G4 includes a cemented lens which formed by abiconvex lens L241 and a negative meniscus lens L242 having a concavesurface directed toward the object side, and has a positive refractingpower as a whole.

At the time of zooming from the wide angle end to the telephoto end, thefirst lens group G1 is fixed, the second lens group G2 moves toward theobject side, the aperture S is fixed, the third lens group G3 movestoward the image side, and the fourth lens group G4 moves toward theimage side.

An aspheric surface is provided on a surface on the object side of thebiconvex lens L213 in the first lens group G1, a surface on the objectside of the biconvex lens L221 in the second lens group G2 and a surfaceon the image side of the negative meniscus lens L222 having the convexsurface directed toward the image side in the second lens group, and asurface on the object side of the biconvex lens L241 in the fourth lensgroup G4.

Next, numerical data of the thirty eighth embodiment will be enumerated.

Numerical data 38 r1 = 39.906 d1 = 1.1 Nd1 = 1.7432 νd1 = 49.34 r2 =9.964 d2 = 3 r3 = ∞ d3 = 12.5 Nd3 = 1.801 νd3 = 34.97 r4 = ∞ d4 = 0.4 r5= 44.825 d5 = 2.13 Nd5 = 1.8061 νd5 = 40.92 (Aspheric surface) r6 =−12.948 d6 = 0.7 Nd6 = 1.52 νd6 = 57 r7 = 15.168 d7 = D7 r8 = 11.641 d8= 5.09 Nd8 = 1.497 νd8 = 81.54 (Aspheric surface) r9 = −29.171 d9 = 0.35Nd9 = 2.05122 νd9 = 6.28 r10 = −33.680 d10 = D10 (Aspheric surface) r11= Aperture stop d11 = D11 r12 = −13.644 d12 = 0.7 Nd12 = 1.48749 νd12 =70.23 r13 = 8.503 d13 = 1.6 Nd13 = 1.83481 νd13 = 40.7 r14 = 18.44 d14 =D14 r15 = 12.109 d15 = 3.5 Nd15 = 1.7432 νd15 = 49.34 (Aspheric surface)r16 = −6 d16 = 0.7 Nd16 = 1.84666 νd16 = 23.78 r17 = −16.133 d17 = D17r18 = ∞ d18 = 1.44 Nd18 = 1.54771 νd18 = 62.84 r19 = ∞ d19 = 0.8 r20 = ∞d20 = 0.6 Nd20 = 1.51633 νd20 = 64.14 r21 = ∞ d21 = D21 Asphericalcoefficients  5th surface k = 0 A4 = 2.13457E−05 A6 = 1.64989E−08 A8 = 0 8th surface k = 0 A4 = −4.96465E−05 A6 = 3.28544E−07 A8 = 0.00000E+0010th surface k = 0 A4 = 1.83684E−05 A6 = 4.02729E−07 A8 = 0.00000E+0015th surface k = 0 A4 = −1.75253E−04 A6 = 4.15528E−07 A8 = 0.00000E+00Zoom data When D0 (distance from object up to 1st surface) is ∞wide-angle end intermediate telephoto end Focal length 6 10.399 17.999FNO. 2.84 3.31 3.72 D7 15.34 8.56 0.8 D10 1.6 8.37 16.14 D11 1.4 5.899.04 D14 6.27 4.18 3 D17 5.57 3.17 1.21 D21 1.36 1.36 1.36

THIRTY NINTH EMBODIMENT

Thus, it is possible to use such image forming optical system of thepresent invention in a photographic apparatus in which an image of anobject is photographed by an electronic image pickup element such as aCCD and a CMOS, particularly a digital camera and a video camera, apersonal computer, a telephone, and a portable terminal which areexamples of an information processing unit, particularly a portabletelephone which is easy to carry. Embodiments thereof will beexemplified below.

In FIG. 77 to FIG. 79 show conceptual diagrams of structures in whichthe image forming optical system according to the present invention isincorporated in a photographic optical system 41 of a digital camera.FIG. 77 is a frontward perspective view showing an appearance of adigital camera 40, FIG. 78 is a rearward perspective view of the same,and FIG. 79 is a cross-sectional view showing an optical arrangement ofthe digital camera 40.

The digital camera 40, in a case of this example, includes thephotographic optical system 41 (an objective optical system forphotography 48) having an optical path for photography 42, a finderoptical system 43 having an optical path for finder 44, a shutter 45, aflash 46, and a liquid-crystal display monitor 47. Moreover, when theshutter 45 disposed at an upper portion of the camera 40 is pressed, inconjugation with this, a photograph is taken through the photographicoptical system 41 (objective optical system for photography 48) such asthe zoom lens in the first embodiment.

An object image formed by the photographic optical system 41(photographic objective optical system 48) is formed on an image pickupsurface 50 of a CCD 49. The object image photoreceived at the CCD 49 isdisplayed on the liquid-crystal display monitor 47 which is provided ona camera rear surface as an electronic image, via an image processingmeans 51. Moreover, a memory etc. is disposed in the image processingmeans 51, and it is possible to record the electronic imagephotographed. This memory may be provided separately from the imageprocessing means 51, or may be formed by carrying out by writing byrecording (recorded writing) electronically by a floppy (registeredtrademark) disc, memory card, or an MO etc.

Furthermore, an objective optical system for finder 53 is disposed inthe optical path for finder 44. This objective optical system for finder53 includes a cover lens 54, a first prism 10, an aperture stop 2, asecond prism 20, and a lens for focusing 66. An object image is formedon an image forming surface 67 by this objective optical system forfinder 53. This object image is formed in a field frame of a Porro prismwhich is an image erecting member equipped with a first reflectingsurface 56 and a second reflecting surface 58. On a rear side of thisPorro prism, an eyepiece optical system 59 which guides an image formedas an erected normal image is disposed.

By the digital camera 40 structured in such manner, it is possible torealize an optical image pickup apparatus having a zoom lens with areduced size and thickness, in which the number of structural componentsis reduced.

Next, a personal computer which is an example of an informationprocessing apparatus with a built-in image forming system as anobjective optical system is shown in FIG. 80 to FIG. 82. FIG. 80 is afrontward perspective view of a personal computer 300 with its coveropened, FIG. 81 is a cross-sectional view of a photographic opticalsystem 303 of the personal computer 300, and FIG. 82 is a side view ofFIG. 80. As it is shown in FIG. 80 to FIG. 82, the personal computer 300has a keyboard 301, an information processing means and a recordingmeans, a monitor 302, and a photographic optical system 303.

Here, the keyboard 301 is for an operator to input information from anoutside. The information processing means and the recording means areomitted in the diagram. The monitor 302 is for displaying theinformation to the operator. The photographic optical system 303 is forphotographing an image of the operator or a surrounding. The monitor 302may be a display such as a liquid-crystal display or a CRT display. Asthe liquid-crystal display, a transmission liquid-crystal display devicewhich illuminates from a rear surface by a backlight not shown in thediagram, and a reflection liquid-crystal display device which displaysby reflecting light from a front surface are available. Moreover, in thediagram, the photographic optical system 303 is built-in at a right sideof the monitor 302, but without restricting to this location, thephotographic optical system 303 may be anywhere around the monitor 302and the keyboard 301.

This photographic optical system 303 has an objective optical system 100which includes the zoom lens in the first embodiment for example, and anelectronic image pickup element chip 162 which receives an image. Theseare built into the personal computer 300.

At a front end of a mirror frame, a cover glass 102 for protecting theobjective optical system 100 is disposed.

An object image received at the electronic image pickup element chip 162is input to a processing means of the personal computer 300 via aterminal 166. Further, the object image is displayed as an electronicimage on the monitor 302. In FIG. 40, an image 305 photographed by theuser is displayed as an example of the electronic image. Moreover, it isalso possible to display the image 305 on a personal computer of acommunication counterpart from a remote location via a processing means.For transmitting the image to the remote location, the Internet andtelephone are used.

Next, a telephone which is an example of an information processingapparatus in which the image forming optical system of the presentinvention is built-in as a photographic optical system, particularly aportable telephone which is easy to carry is shown in FIG. 83A, FIG.83B, and FIG. 83C. FIG. 83A is a front view of a portable telephone 400,FIG. 83B is a side view of the portable telephone 400, and FIG. 83C is across-sectional view of a photographic optical system 405. As shown inFIG. 3A to FIG. 83C, the portable telephone 400 includes a microphonesection 401, a speaker section 402, an input dial 403, a monitor 404,the photographic optical system 405, an antenna 406, and a processingmeans.

Here, the microphone section 401 is for inputting a voice of theoperator as information. The speaker section 402 is for outputting avoice of the communication counterpart. The input dial 403 is for theoperator to input information. The monitor 404 is for displaying aphotographic image of the operator himself and the communicationcounterpart, and information such as a telephone number. The antenna 406is for carrying out a transmission and a reception of communicationelectric waves. The processing means (not shown in the diagram) is forcarrying out processing of image information, communication information,and input signal etc.

Here, the monitor 404 is a liquid-crystal display device. Moreover, inthe diagram, a position of disposing each structural element is notrestricted in particular to a position in the diagram. This photographicoptical system 405 has an objective optical system 100 which is disposedin a photographic optical path 407 and an image pickup element chip 162which receives an object image. As the objective optical system 100, thezoom lens in the first embodiment for example, is used. These are builtinto the portable telephone 400.

At a front end of a mirror frame, a cover glass 102 for protecting theobjective optical system 100 is disposed.

An object image received at the electronic image pickup element chip 162is input to an image processing means which is not shown in the diagram,via a terminal 166. Further, the object image finally displayed as anelectronic image on the monitor 404 or a monitor of the communicationcounterpart, or both. Moreover, a signal processing function is includedin the processing means. In a case of transmitting an image to thecommunication counterpart, according to this function, information ofthe object image received at the electronic image pickup element chip162 is converted to a signal which can be transmitted.

As it has been described above, the image forming optical system of thepresent invention, and the electronic image pickup apparatus in whichthe image forming optical system used have the followingcharacteristics.

(1) It is characterized in that, instead of condition (1a), thefollowing conditional expression is satisfied.

1.48<β<2.04

Here, Nd denotes a refractive index of a glass used in a cemented lens,νd denotes the Abbe's number for the glass used in the cemented lens,and a relation Nd=α×νd+β is satisfied.(2) It is characterized in that, instead of condition (1a), thefollowing conditional expression is satisfied.

1.50<β<2.00

Here, Nd denotes a refractive index of the glass used in the cementedlens, νd denotes the Abbe's number for the glass used in the cementedlens, and the relation Nd=α×νd+β is satisfied.(3) It is characterized in that, instead of condition (2a), thefollowing conditional expression is satisfied.

1.58<Nd<2.10

Here, Nd denotes the refractive index of the glass used in the cementedlens.(4) It is characterized in that, instead of condition (2a), thefollowing conditional expression is satisfied.

1.63<Nd<1.95

Here, Nd denotes the refractive index of the glass used in the cementedlens.(5) It is characterized in that, instead of condition (3a), thefollowing conditional expression is satisfied.

5<νd<10

Here, νd denotes the Abbe's number for the glass used in the cementedlens.(6) It is characterized in that, instead of condition (3a), thefollowing conditional expression is satisfied.

6<νd<9

Here, νd denotes the Abbe's number for the glass used in the cementedlens.(7) It is characterized in that, instead of condition (1b), thefollowing conditional expression is satisfied.

1.48<β<2.04

Here, Nd denotes the refractive index of the glass used in the cementedlens, νd denotes the Abbe's number for the glass used in the cementedlens, and the relation Nd=α×νd+β is satisfied.(8) It is characterized in that, instead of condition (1b), thefollowing conditional expression is satisfied.

1.50<β<2.00

Here, Nd denotes the refractive index of the glass used in the cementedlens, νd denotes the Abbe's number for the glass used in the cementedlens, and the relation Nd=α×νd+β is satisfied.(9) It is characterized in that, instead of condition (2b), thefollowing conditional expression is satisfied.

1.60<Nd<2.10

Here, Nd denotes the refractive index of the glass used in the cementedlens.(10) It is characterized in that, instead of condition (2b), thefollowing conditional expression is satisfied.

1.63<Nd<1.95

Here, Nd denotes the refractive index of the glass used in the cementedlens.(11) It is characterized in that, instead of condition (3b), thefollowing conditional expression is satisfied.

5<νd<30

Here, νd denotes the Abbe's number for the glass used in the cementedlens.(12) It is characterized in that, instead of condition (3b), thefollowing conditional expression is satisfied.

6<νd<25

Here, νd denotes the Abbe's number for the glass used in the cementedlens.(13) It is characterized in that, instead of condition (7), thefollowing conditional expression is satisfied at the time of almostinfinite object point focusing.

0.75<y ₀₇/(fw·tan ω_(07w))<0.94

where, y₀₇ is indicated as y₀₇=0.7y₁₀ when, in an effective image pickupsurface (surface in which, image pickup is possible), a distance from acenter up to a farthest point (maximum image height) is let to be y₁₀.Moreover, ω_(07w) is an angle with respect to an optical axis in adirection of an object point corresponding to an image point connectingfrom a center on the image pickup surface in a wide angle end up to aposition of y₀₇.

(14) It is characterized in that, instead of condition (7), thefollowing conditional expression is satisfied at the time of almostinfinite object point focusing.

0.80<y ₀₇/(fw·tan ω_(07w))<0.92

where, y₀₇ is indicated by y₀₇=0.7y₁₀ when, in an effective image pickupsurface (surface in which, image pickup is possible), a distance from acenter up to a farthest point (maximum image height) is let to be y₁₀.Moreover, ω_(07w) is an angle with respect to an optical axis in adirection of an object point corresponding to an image point connectingfrom a center on the image pickup surface in a wide angle end up to aposition of y₀₇.

INDUSTRIAL APPLICABILITY

An image forming optical system according to the present invention isuseful in an optical system with a reduced size and thickness (madethin), and furthermore, an electronic image pickup apparatus of thepresent invention is useful in an apparatus in which both a favorablecorrection and a widening of an angle have been realized.

1. An image forming optical system comprising: a positive lens group; anegative lens group; and an aperture stop, wherein the positive lensgroup is disposed at an object side of the aperture stop, and thepositive lens group includes a cemented lens which is formed bycementing a plurality of lenses, and in a rectangular coordinate systemin which, a horizontal axis is let to be Nd and a vertical axis is letto be νd, when a straight line indicated by Nd=α×νd+β (where, α=−0.017)is set, Nd and νd of at least one lens forming the cemented lens areincluded in both of areas namely, an area which is determined by a linewhen a lower limit value is in a range of a following conditionalexpression (1a), and a line when an upper limit value is in a range ofthe following conditional expression (1a), and an area determined byfollowing conditional expressions (2a) and (3a)1.45<β<2.15  (1a)1.30<Nd<2.20  (2a)3<νd<12  (3a) where, Nd denotes a refractive index, and νd denotes anAbbe's number.
 2. An image forming optical system comprising: a positivelens group; a negative lens group; and an aperture stop, wherein thepositive lens group is disposed at an image side of the aperture stop,and the positive lens group has a cemented lens in which a plurality oflenses are cemented, and in a rectangular coordinate system in which, ahorizontal axis is let to be Nd and a vertical axis is let to be νd,when a straight line indicated by Nd=α×νd+β (where, α=−0.017) is set, Ndand νd of at least one lens forming the cemented lens are included inboth of areas namely, an area which is determined by a line when a lowerlimit value is in a range of a following conditional expression (1b),and a line when an upper limit value is in a range of the followingconditional expression (1b), and an area determined by followingconditional expressions (2b) and (3b)1.45<β<2.15  (1b)1.58<Nd<2.20  (2b)3<νd<40  (3b) where, Nd denotes a refractive index, and νd denotes anAbbe's number.
 3. The image forming optical system according to one ofclaim 1 and claim 2, wherein when the one lens of which Nd and νd areincluded in both the areas is let to be a predetermined lens, a centerthickness of the predetermined lens along an optical axis of thepredetermined lens is less than a center thickness of the predeterminedlens along an optical axis of the other lens of the cemented lens. 4.The image forming optical system according to claim 3, wherein the imageforming optical system satisfies a following conditional expression0.22<t1<2.0 where, t1 is the center thickness of the predetermined lensalong an optical axis of the predetermined lens.
 5. The image formingoptical system according to one of claim 1 and claim 2, wherein thecemented lens is a compound lens which is formed by closely adhering andhardening a resin on a lens surface of the one lens which forms thecemented lens.
 6. The image forming optical system according to one ofclaim 1 and claim 2, wherein the cemented lens is a compound lens whichis formed by closely adhering and hardening a glass on a lens surface ofthe one lens which forms the cemented lens.
 7. The image forming opticalsystem according to one of claim 1 and claim 2, wherein the imageforming optical system is a zoom lens of which a closest side toward anobject is a positive group.
 8. The image forming optical systemaccording to one of claim 1 and claim 2, wherein the image formingoptical system is a zoom lens of which a closest side toward an objectis a negative group.
 9. The image forming optical system according toone of claim 1 and claim 2, further comprising: a prism for folding. 10.The image forming optical system according to claim 9, wherein the prismis in a lens group on a closest side toward an object.
 11. An electronicimage pickup apparatus comprising: an image forming optical systemaccording to claim 1 or claim 2; an electronic image pickup element; andan image processing means which processes image data obtained by imagepickup by the electronic image pickup element an image which is formedthrough the image forming optical system, and outputs as image data inwhich a shape is changed upon processing, wherein the image formingoptical system is a zoom lens, and the zoom lens satisfies a followingconditional expression at a time of infinite object point focusing0.7<y ₀₇/(fw·tan ω_(07w))<0.96 where y₀₇ is indicated as y₀₇=0.7y₁₀when, in an effective image pickup surface (surface in which, imagepickup is possible), a distance from a center up to a farthest point(maximum image height) is let to be y₁₀. Moreover, ω_(07w) is an anglewith respect to an optical axis in a direction of an object pointcorresponding to an image point connecting from a center on the imagepickup surface in a wide angle end up to a position of y₀₇.